SORTED: A KTM 525 EXC OR SOMETHING ELSE

I see lots of KTM 520 or 525 EXC's on Gumtree... are any of them yours for I fancy some of these KTM's and would like more info from the gang. I am looking for something in this class 400-500 cc. and below R20k. What can I expect and what should I look out for? I need a reliable farm bike mostly for the purpose of work (but the idea is to find a more exciting reason for getting up in the morning... hehehe!). The distances that I need to travel are around 80km per day some open gravel and some of it trails thus a two stroke will not work, I guess.
What other bikes are good options? For instance a CRF or WR but these are a bit pricey.