I just got to play a Factotum today in an RPGA game (Crimson Codex adventure, I didn't expect to play the character again since I usually only play in the Cabal games). The Factotum had seemed weak to me, but I was still interested in trying it and this seemed like a great chance.
I'm really happy with how it came out. I played a level 4 human factotum, and the class was pretty good. There were only two combat encounters. I managed to deal 25 damage on a longbow crit... Inspiration point for 4 bonus damage + x3 crit multiplier = dead NPC.
I could have used some better spell selection... I chose detect magic and color spray, and never got a chance to use either. The bonus to skill checks came up a fair amount of time, although due to poor rolling it didn't help much. I actually did get screwed over by the once per day thing, because I used diplomacy early on and then needed it later that day.
Oh, the +4 to str and dex-based skill checks is fantastic. I had a +13 hide and move silently (+2 dex, 7 ranks, +4 int). Also just occurred to me that I totally forgot to write down any synergies I may have had... Even the bonus to strength checks came in handy, allowing me to win an arm wrestling contest and topple a make-shift barricade onto an enemy.
Of my 77 skill points, I put 7 ranks in each of 9 different skills and then 1 rank in each of 14 different skills (you need 1 rank in a skill to use inspiration with it).
Never used the sneak attack option, although now that I think about it I had a great opportunity to in the last encounter.