I use Weatherbug but I haven't noticed any problems. I've actually been impressed with what a cool app it is. I used to use Weather Channel but I think I like Weatherbug more. What kind of problems are people having with it?
For him, the entire OS of the phone seemed to...well, implode. Soon after installing it, certain apps wouldn't even open (including native apps, like market and camera), while others would. The entire OS was laggy and didn't respond to a lot of clicks.
We're not 100% sure it's tied to weatherbug, but based on people's reports on the forums, we're leaning that way like we've been drinking V8 in the 90's.
In my experience as a heavy PC user as well, the weatherbug app is generally poorly coded and very heavy (think norton antivirus) so if the same developers are on the phone version, I can only imagine it's not so great code-wise. Of course, individual mileage would vary - he could have one of the phones from the theorized "bad batch" or just have a lemon in general. But, FWIW, since uninstalling weatherbug (as well as a bunch of other apps, to be fair), he's been sailing pretty smooth.
So far I'm personally pretty happy with the weather channel widget - very small and simple and to the point. But I'm not a heavy user of the weather widgets, I just like to see what it's gonna be like outside tonight and tomorrow morning, very little beyond that.
[edited to expand on 3rd paragraph some]