Best bang for buck would have to be Rock Island Armory. Can be had for just over $400, goes bang every time I take it to the range, and all modifications that can be done, and that are done to higher end models, can be done with ease to RIA's. I currently have 2 1911's, one full size from RIA, and a Detonics Combat Master. The triger, sear, firing pin, break down lever, frames, everything will interchange (with exception of the Detonics Mag's will not work in the RIA, due to being too short.)
If you are in the 600-800 range, I would still recommend a RIA, as you can use that extra 200-400 on some VERY nice upgrades.
But for an out of the box gun in your range, I believe you would be happy looking at Springfield's. There lower end 1911's are towards the bottom of your budget, and fire well out of the box. You would have less left for upgrades, but the machine work is of slightly better quality. My experience has been the tolerances are the same between the stock Springfield's, and RIA's, just sometimes the RIA's need a little TLC right out of the box. Mine fired fine, but I polished the feed ramp a little as it had some tool marks.
I believe another firearm that may be in your price range would be para ordnance, but I have read nothing but negative reviews of their products for the last 3 years, so I would not recommend them.
To recap, I have a RIA in full size, worth 400 new, and about 250 in mods done to it. I have over 10k rounds through it, and it lives on the cheap range ammo (maby one or two fail to eject every 100 rounds), and fires my carry ammo 100% with out issues.