How are you finding it, Hulver?
I'm pondering the 350 to 550 upgrade if I can get my darkroom equipment sold. Had a look on ebay and the prices are mad! Don't really understand why people spend £400 for one on there when mpb have bodies for about the £300-325 mark that come with a 6 month warranty...
I love it. I did upgrade from a very old 300d though, so it's quite a big change. The body is smaller than the 300d, which makes it a tiny bit awkward with my massive hands, but it's not an issue when I'm shooting.
Other than playing with some settings and forgetting to set it back, I've not had a problem with it. I can do more with it than I could the 300d, and I enjoy taking pictures with it very much.
I'd highly recommend reading the manual though. There's a lot there, I feel like I've hardly scratched the surface of what it can do.
For practical things, I find the menu system easy to use, although I don't use many features beyond changing the flash power, AEB and changing the white balance.
The battery seems to last forever, which is a good job, because it's different from the battery in the 300d and the 30d, so none of my spares fit.
Continuous shooting takes lots of pictures, and having HD video is a nice toy, but I've hardly used that yet.
The screen is nice and big and clear, so you can get a good look at the stuff you've shot. I rarely use the live view, although it has come in handy on two occasions.
I love the flash, and the 18-55mm lens with IS is great.