XP isn't going to be supported in a few years. Vista will be superseded next year (or, judging by Vista's release delays, 2011-12).
Vista's never crashed on me and does rather well for itself. I use Vista Ultimate x64 so if there are going to be problems it'll be Vista-related and 64-bit related but I have none. XP has its benefits but the 64-bit version sucks.
If you're using a PC with up-to-date software and hardware, Vista does you well. If you're back-dating hardware and/or software by a few years, use XP or an older OS.
Which is better? Try them both out for yourself. If XP works fine for you, you can make up your own mind whether to upgrade. If you ask others about which is better between the two you'll never come to a conclusion due primarily to opinions from fanboys, novices and businesses. Any other bad opinions on either OS are usually from people with bad luck or incompatibilities.
Am I cranky? No, there's no tone of voice in text and I couldn't be bothered to elaborate.
