the atomik nitrous and the pitpro xr (klx version) and the normal pitpro 140 are entry level bikes. and nothing has really changed on them for the last 2 or so years.
meaning everything about them is pretty standard, specially the suspension which is what makes a half decent bike to ride...
if you've got 1300 to spend on a bike then id suggest you take a look at the DHZ range of bikes and maybe add some coin to the 1300 to get a bike with decent suspension...
especially the crf70 style bikes as they are the newest on the market..
but if your just bashing around a paddock or in the bush then the nitrous or pitpro will go ok but you'll find yourself upgrading the suspension in no time..
one thing to add is that the reviews you've read are probably from people thinking they were buying a top of the range bike, which they are far from..
just remember.. you get what you pay for.. even with china bikes..