I just upgraded my blog from WordPress 1.2 to 1.5. As expected, the actual upgrade was very smooth, and it really didn’t take longer than a few minutes.
In the next few days, I’ll need to play with WordPress’s new theme mechanism to customize the design of my blog. I tried a bunch of themes (there are a lot of 1.5-compatible themes already, many of them very nice), but none of them were usable without at least a little bit of tweaking (for example to insert my logo at the right place, customize colors to match, etc.).
So for now, I’m sticking with the default design (which is quite elegant but looks like about 100,000 other blogs out there…).