I have a Simmons 600 that I paid like $120 for 5 years ago. It will show up to 600 if you have a good target (house, billboard). It will do about 275 at a large tree. Where I hunt, 200 yards is the longest shot I can take. I bought it to find this exact info, so I could set a zero on my scope, so it was worth what I paid.
I'm no expert, but in my experience, they will accurately range a game animal at about 1/2 the distance they are rated for. As said if it is rated for 600 yards that is about right for a large object, but 300 yards on a deer is pushing it.
I have an older version of this. It works well out to 300-400 yards. Beyond that not so much. Sometimes you can range a large object near the target at longer ranges to get a more accurate estimate. But that isn't always possible. But it does what I need and I'm happy with it.
I have a Halo XTR1500 and a Sig Kilo 1600 , have had them about 6yrs. The Sig is about $100 more than the Halo. Both will range deer and large trees out 500 to 600yds, I have ranged a car at 1000yds with the Sig. The Sig is a little clearer optics and does reach out a little further. The Kilo 1600 is not available now, but the Kilo3k is a comparable model.
I've been very happy with the Sig Kilo 1600 I bought a few years ago. The Kilo 1600 has been discontinued but is still available direct from Sig's website. The Sig Buckmasters 1500 is what replaced it. I have no complaints about the Sig Kilo 1600.
Just keep in mind that the range on animals will be about 1/2 to 2/3 distance of what they are rated for no matter which brand you go with.
I bought a cheap Walmart one years ago and have yet to need anything else. A Simmons, it's accurate as heck at short and medium distances and on houses at 1000 yds. Unless you're going to be ranging things at large fractions of a mile, don't overspend!
I agree with everyone else about them registering about 1/2 what their ratings are, I have a Simon's and Bushnell and a friend has a Sig and each will range a target at about 1/2 their rated range but something big and bright will work out to the advertised maximum range (log cabin is not bright enough but tin roof is). I like the Bushnell and Sig for their clarity but carry the Simon's in my bag when I go hunting or to the range (cheap and easy to use)