i'm fairly happy with mine, the only strangeness is a slight stutter in ogl apps. i've never been able to get rid of it completely in the year i've had this board. overall for the price i'd say it's been a great board, overclocks very well, very stable, and all this with a crappy old 250w psu. i'll be looking for shuttle to produce an n-force board as that will almost definately be my next choice for chipset. i'd recomend them and i'd buy their products again. guess i'd have to give the ak31 v3.1 an 8 on a 1-10 scale.
i own and still use 2 shuttle ak31's, and they have yet to let me down.. in their prime you'd be hard pressed to find a better performing/overclocking/cheaper board out there... however god help you if you get a bad unit, in my experience working on them, they either work great, or have all kinds of problems.. theres little to no in between...
I liked my AK31 v3.1 while I had it, but in retrospect it was extremely quirky. It took a voltage mod and a month and a half of running it in my secondary box to get everything tweaked out to get it to work right. My Abit and my Asus have both worked extremely well OOTB.
As far as KT266A boards go it's a fair choice but there are newer boards that are better choices at this point. Shuttle has done well to shake the "cheap" reputation but they're not to the point of an Abit, Asus or an MSI yet.
I agree with sickboy's last comments. I ran an ak31 for a while and it was very good for the price. Went up to 150fsb stable for me, but I was running cheap *** memory at the time so that was holding back the OC. The board itself performed fine and it's still running fine, but not overclocked anymore 'cause I put it into a budget box I made for a friend.
Right now, I'm in love with my current Epox board. It ran 24/7 at 200fsb easy with an unlocked 1800+ (9x200). Life is a little different with my 2400 in there, but the board is still sweet. If I were gonna build a budget system, I'd do it with an 8k5a2 and a 1600+ ($53ish at newegg...can't beat that with a stick), unlock it, drop the mult and crank the fsb as far as my memory will allow.