That's interesting about the speed - I'm running in Firefox 3.5.1 and it seems snappy.
My main disappointment with it, so far, is that the music player doesn't work. I was going to use it as a place to hold my large mp3 collection and play from that interface. They give you 15GB of space, so I was hoping to use it better.
Other than that, I think it's cool how you can link your Google documents and access them in a manner that you would from the folders on your desktop OS. It even preserves the folder structure that you have with your Google documents.