I myself have decided to take the plunge with Concept FX. Been running around a month or so, and not too bad so far. There's been a couple of howlers (EURGBP) that lost both time rapidly, and a few others that I didn't take (thankfully) because they didn't make sense (ie system already long EURUSD, and telling me to short GBPUSD). I missed one good entry because I couldn't be arsed to setup my platform on a Sunday night, and the entry was trigged at 7am on the Monday, when I was still asleep. One trade is open at the moment. Been negative all day, however in the last 15 mins it has just about turned positive.
I'll personally be giving this system 6 months, but so far so good.
One very frustrating point is Concept seem to take an age to update their results page on the website, so I'm still a little dubious about the results. However time will no doubt tell.