Ahh, the magazines...you see, JMB put that dimple on the follower to hold that last rd in place and not let it get ahead of the extractor especially as the mag spring gets weaker....now, as you see, a lot of folk's pistols run fine with mags that don't use that dimpled follower but, when their springs weaken they may be feeding some of those rounds by being pushed by the extractor and causing the extractor to have to jump over the rim of the cartridge and not even know that this is happening...then one day the extractor has lost it's proper tension and the pistol starts to malfunction or worse, it breaks and there you are. If the pistol is just a range gun, this is of less concern than if it is for defensive use. Putting 8 rds in a space where 7 were designed to be means compromising somewhere and that can affect reliability.
Anyone ever find a live round laying on top of the mag or on the ground and the slide locked open when you thought you had one more round to fire?? That's caused by a weak mag spring that let the rd come out of the mag when the round before it was ejected...and if it's weak enough not to hold that last round in place, then the extractor has probably been pushed over the rim of some cartridges already....time for some new mag springs and to check that extractor.
I just prefer to have all of the designed advantages of the 1911 working in my favor if I'm gonna use the pistol for serious purposes and that means a 7 rd mag with a strong spring and a dimpled follower. Will other mags work?, it really depends on the pistol and ammo, but the standard for a reliable 1911 is the 7 rd mag with a dimpled follower and ball ammo ... deviate from there and you just have to see for yourself with your pistol. Some 1911 style pistols come with a 7 rd dimpled mag and the new pistol won't work with it, sometimes it's a bad mag but more often it's a bad extractor or the pistol just needs to be worked a little - sad, but now most of the factories think we should break in the pistols with a lot of rds before we deem there to be a problem. I just do a detailed inspection and smooth or tweak if need be (unless something major shows to be a potential problem) before an initial range session. A factory supplied 7 rd dimpled follower mag should function...now that I think about it, the only manufacturers I Know for a fact supplies this type mags with some of their pistols are Colt and Springfield Armory...Kimber's come with 7 or 8 rd mags but no dimple on the follower, I haven't seen their newest tactical mags that people report work well.
Anyway, when you find what mags work reliably with your pistol with the ammo you are gonna use, then clean and keep those mags for serious use and use another set of (preferably the same type) mags for the range.
Feeding problems will usually show up with either the first or the last rd of the mag. I do not keep my carry mag topped off for that extra little bit of reliability from not having a full mag pushing against the bottom of the slide possibly slowing it down just in case I was to have a weak hand grip on the pistol in a SHTF situation...plus you got somewhere to put that chamber rd if you have to clear your weapon for whatever reason.
Lots of different mags out there and there will be people who swear by all different ones and some that swear at them! ..