Too bulky, and still a lot of compatability issues. There's no reason for an OS to use that many resources. I'd take XP almost always over Vista.
I do love some of the new things Vista has though, like automatic recovery after BSoD 
It also automatically fixes itself if the boot sector stops working, which I don't understand, but also love.
If you bought a machine in the past three years, you can run Vista no problem. It scales quite nicely. It has a bit too much with it, I agree, but there is almost no performance issues compared to other OS's on current machines. Vista has a ton of good features that puts it above XP, IMO. The main is its stability. I haven't had to reformat my Vista machine in over a year. My XP machines with similar or less use need to be reformatted about every 4 months. Add all the small things it does right- font rendering, navigation, aspect ratios, icon flexibility, bit locker, calendar, media center, mobility center, etc. As for compatibility issues, that is definitely not Vista's fault. People expect the same software to work that worked on 3.1. That's asinine. Vendors had years to develop proper drivers. But hey, atleast you have the option to upgrade your computer. It's your fault if you buy something that is not supported, or own it while buying Vista.
