What in particular would you like to know? If you don't have specific questions it would be easier for you to just check out Microsofts site.
My impressions from my time with vista (I worked with it a little in Beta, and adopted early on as a secondary os):
It uses more resources, but utilizes them better. If you have under 1GB of ram you'll be bogged down, but when you're utalizing 1-2Gb of ram and multitasking a lot, it can handle it better than XP.
Legacy hardware is a problem, If you have old peripherals (printers, webcams, scanners, ect,... ) you'll have a hard time finding drivers.
Older software has the same problems as hardware, if it's not compatible it's not compatible. Most softwre you would buy now is vista compliant, but if you have programs that you REALLY need to keep using, do the research and make sure they'll work with vista.
It's pretty. If you want the new shiny features, and have the resources for it, it's cool.
Be careful which version you get, do the research and make sure you get the features you need (home basic is practically XP home stripped down)
If you're wondering about issues with it, browse this section of the site and look at what people are complaining about.
Get back with specific questions, and we'll do what we can to answer.
PS: I still don't recommend Vista to people who aren't comfortable playing with it. My uncle works in web-design and light software support at IBM, he calls me twice a week about his new problems adopting Vista. There's a reason OEMs are fighting to keep selling XP, it just works more smoothly