i have the same MBP as yours. a mid-2010 15" MBP i7 2.66 Ghz cpu & GT330m nvidia dGPU w/ 512 MB of VRAM.
and you know what? this MBP kernel panics more than my 12" powerbook w/ 1 Ghz G4 cpu which is still kicking and maybe KP'd once or twice in the 10 or so yrs that it's been running. the only thing is that this powerbook can't play videos on the internet without stutter.
i think apple is screwing up these model MBP's with how either open cl or open gl interacts with the gt330m. i can play starcraft 2 on it without kernel panicking but using fcp x or motion 5 instantly causes it to KP.
so my vote goes to the 12" powerbook.
PS--it's not how fast your computer is but how reliable it is. it doesn't matter if the computer can go 1 trillion gigahertz if it just crashes.
pss--call it nostalgia but os x tiger and powerpc seems so much stabler than the combination of intel cpu's and the new os x in these new supper slim and glossy macbook pro or nonpros of today.
psss--i'm blaming the core programmers of os x leaving over the yrs, so os x is buggier, also the yearly new os x cycle is creating or leap frogging issues that dont get fixed, the death of steve jobs causing a leaderless headless multibillion company with no more vision, just flapping around like that flappy something game, and intel cpu's are architecturally more complex than the RISC-based powerpc of yore, thus less stable, more buggy, etc., etc.
It also doesn't matter if the computer is reliable if it is irritatingly slow or is not longer capable of performing some functions due to its specs.
(Not saying that specifically about the powerbook, but older computers in general).