among your chosen 3, each has its own panel type,
Acer is IPS (good accuracy but average response times)
Samsung is VA (super fast response, but less color accurate frames)
LG is TN (speed and color in the middle of both other panels)
samsung is rocking the whole curve gimmick. dont see any functional use for it, budget wise acer looks good, my experience with LG is not that great but my friends have good things to say about it. Im on an acer one myself.
As for bad reviews about acer, i assume they are talking about the backlight bleed. Mine has some, ive seen it on my friends dell too, many monitors will have it in some small form or the other.