XP goes end of life April 2014 .. so with no patches.. you will need move to a new OS before then.
Win8 is not so much "buggy".. but it is very different to what you are used to and the discussion rages on if it is better than Win 7.
Really up to personal preference .. but if you don't like new ways of doing things.. stay with Win7..if your machine has touch interface or you enjoy learning new ways to work your computer.. go with Win8.
Just my 2c
HTH
Cheers