Everything you need to know about optics buying-
My take...
I've been around the block a few times and owned a LOT of guns and a lot of glass. Most of it has been in the lower end to mid level with a few exceptions. My bosses stuff all has Leupold in the $400-800 range. I use pretty exclusively Nikon scopes. The prostaff line is "OK +" it doesn't look nearly as good as the buckmasters line. Fewer bells and whistles...it's like Nikons equivalent to Tasco "World Class or world class plus" which used to be decent scopes to years ago in the sub $200 range..about $89 for the 3-9x40 I put 1400+ rounds through my .30-06 with before it had any issues (dunno how they are today) Bushnell stuff...junk It's the line I see the most complete failures and regularly see failure to hold a zero. The B&L elite series 3200 and up -those where good. I believe they call them Bushnell now which seems kind of a shame to me. BSA stuff runs the gammit from decent to poorly designs junk and quallity control is a lot better these days but still not on par with the better scopes (like Nikon buckmaster and up) If you want something dirt cheap until you can buy a real scope that you can throw on a .22 later they are a decent econo scope...I personally wouldn't hunt with one but I've seen some rimfire guys that use em all the time with good results.
If you can buy a Nikon...prefferably a buckmasters 3-9x40 IMHO I've owned the monarch scopes...dang good but the buckmasters adjust and hold just as well with 95% of the optical quallity for about half the price. It's well worth the $40-60 more than the same scope in the prostaff line. I have a team realtree 3-9x50 that is essentially just a camo prostaff on my 7 mag It is "adequate" dusk to dawn. If it's light enough to see and ID a deer you can get the shot. It adjusts and holds precisely. It's alos less clear and bright than my 3-9x40 Buckmasters on my Rem700 .270 or a burris FF II for comparison. I bought it for $75 off a bud that used it a few hunting trips after I mounted it until he upgraded to $1200 glass on his browning...I wouldn't have paid asking prioce for it over a buckmasters but for $75 in the box with free leupold rings I couldn't pass it up so I used it. I REALLY like the buckmasters better...the crosshairs show up better and it's brighter and clearer with better contrast and color. I also like the re-zeroable compact turrets under the dust covers as I can setup a rangcard for a given rifle at various ranges. Very handy. The buckmasters and up adjust and "shoot the box" just as well as a leupold does (varX III is what I test against)
The monarch line in even better but quite a jump in price. The leupold VXIII is brighter and you get 5 minutes more for it. However unless you have the heavy duplex option you won't be seeing your crosshairs for those 5 minutes without a lot of luck. The nikon BM and monarch crosshairs seem easier to find at "dark:30" The color balance and contrast to me looks much better on the monarch than the VXIII line -They look like a Sony Trinitron TV vs. a magnavox or GE. The leupold looks like a trinitron with the brightness pegged on 98% and you get less natural color and contrast for it but sometimes it pays off...assuming you can see the crosshairs...the heavy duplex really does work better IMHO in that line. For the money I like the monarch better...but I'm not sure it's worth the increased price from a buckmaster unless you only own one rifle or this is for your "favorite rifle" in which case....
Zeis conqueest...
It's the best of the Leupold and Nikon Monarch attributes together in one scope. It has great natural color and contrast with amazing clarity (far better than either of the other two) AND is VERY bright but without looking "washed out" for it. For what they go for if I was going to spend more than $200-300 I'd DEFFINATELY save my pennies and buy a Zeis Conquest...over my favorite Nikons or any of the bosses expensive Leupold stuff (which is honestly medium quallity dependable optics when you cut through the name-brand hype...most high end European glass and some Japanese glass bests it by far and sometimes for the same or only a few hundred more depending where in the line you are shopping...sometimes less if you shop hard on some of the japanese stuff).
Summary- Nikon buckmasters and Burris fullfield II lines are the best bang for the buck in the $200-350 range (depending on the type of scope you are hunting for...a 3-9x40 runs you about $200 in either line with options available up from there to the moon. I like Nikons look better but the Burris is certainly a fine scope and several guys at the club preffer them in that price range. Don't spend less but don't spend more unless you buy a conquest. Nothing Leupold makes lower than the VXIII would be something I'd buy...some II's look better than others...some go back a few times others work 100% for decades. The III seems to be most Americans "gold standard" for quallity reliable optics. They are dang good scopes...I just don't personally think they represent a good bargain.
Everything I use right now or would buy this year including scopes & binocculars to range finders is Nikon. I've never had a failure or lost a shot opertunity that a variX III would have got me in the field. However the boss has traveled extensively with Leupold and can say the same...only failures he's had have been from damaged mounts (sad story on a hunt out west...took 9 shots to get his deer...not the one he was AIMING at but...LOL)
One thing I have learned from brother Larry who has spent tiome with some great hunters and great guides is
if you are going to spend insane money on optics for hunting make it your binocculars My nikons are "OK" kinda like "Steiners ar OK" and Leupold stuff is "OK" you can count on all of them and they look way better than cheap stuff and have way better quallity throughout. Until you pickup a set of Swarovski's GOOD LORD!! I've sat on the powerlines at the club off seaon watching deer at 400-700 yards with them in my truck I couldn't even see in the steiners or Nikons and couldn't tell they were deer witha Leupold gold spotting scope! Larry's seen a LOT of deer and other animals he'd have NEVER picked out or seen without them. So my advice is buy buckmasters or a conquest and be done with it and start saving for REALLY good binocculars. Because THAT is where the big money nets you real rewards in the field.
Does size matter? 40mm....50mm....56mm??-
Generally a scope of the same quallity with a correctly designed and matched set of lenses in 50 will pass on more light at the small end than the same in 40mm. In reallity I don't generally see the net gain. Especially in sub $400 scopes. It's harder to get a high quallity lense as perfect as you want it in larger sizes...it takes more attempts and there is a higher reject rate...that is why it costs more to move up. A very good to excellent quallity scope is going to be plenty bright clear and balanced whether it's a 32mm or a 50mm. I like to mount a scope as low to the bore as possible. Truth be told a high quallity 2-7x32mm is probably all any deer hunter really needs. But I plink quite a bit and do some longer range jug shooting a few times a year...and while I'm not willing to lug around a heavier bulkier 4.5-14x40AO the other 98% of the time I do seem to like the classic 3-9x40mm just about beter than all other setups.
I like the fast focus eyepiece and I like compact turrets thet can be re-zeroed (I hate TALL varminter/wanna be sniper turets. Most of my rifles hunt 3-4 months of the year. If I shot rodents all day I might like the latter...just not my thing...for yotes my deer rifles do just as well...no need for a crazy 12-15 pound beanfield rifle IMHO. I've also noticed not all Nikon or Burris scopes are created equal reguardless of size but especially in 50mm. If you look through half a dozen you will almost always see one that just doesn't look "quite as good" and one or two that seem to be "better somehow". It pays to hand-pick in this price range. That can make more difference by far than 40mm vs. 50mm I started noticing this a few years agon when our pre hunting season scope shipments came in. It pays to pick the beter ones as floor models (so I can buy them cheap at the end of season when it's the last one left...I mean to help me sell more scopes!-LOL) Seriously though...not a HUGE difference but a noticable one...A/B enough and you'll see it. Once you get to fine European optics they just all kick butt...at that price they dang well ought to though.
As Forrest Gump would say....that's all I have to say about that!