Opinion lang po mga bossing. In my 10 years working with computers - mula sa simpleng pagbabantay ng computer shop up to being a Tier 2 sa isang Technical Support business - I can say that the stability of an operating system depends on a lot of factors such as your hardware, the software applications you load and your computer lifestyle/habits.
Ang isang main na disadvantage lang kasi ng Windows Vista is that the hardware requirements for it to work is very high. Kaya kung naka Windows XP ka currently, at ung hardware specifications mo eh saktong=sakto lang, talagang maayos ang takbo nung XP mo, pero if you upgrade to Vista with the same Specifications, malamang baka na-meet mo lang ung minimum requirements ng Vista. Hence, hindi mo ma-aachieve ung OPTIMUM performance ng PC mo.
So, basing from these facts, I have 2 suggestions:
1. If you want to have a more stable and optimum performance (assuming that there are no bugs or whatsoever) then upgrade to Vista PLUS upgrade your hardware.
2. If your hardware does not meet or just meets the minimum requirements for Vista, then stick with XP.
I hope this helps. It may not be that much or maybe some don't agree, but this is just an honest opinion. Thanks!