OS upgrade should I ?

I am using XP-SP3 fine and I now run into a little issue that I would like to spend some time for Window Phone 7. This however needs only Windows 7 or Vista versions. I don't see any benefits from upgrading my XP to Ultimate Windows 7. My system has a pretty many installed applications, I am worried the version after the upgrade becomes slower in performance. Any advice please??

Any upgrade to a new OS tends to be slower because newer OSes have more features which require more processing. Since XP was already dropped by Microsoft in support, any new tech and software changes in the future will best be supported under Windows Vista, 7, and 8.