New versions have been popping up a lot lately. My current OS is under my name. Just keep an eye out and you'll find some betas to try out too, but don't post links or ask for links to them.
Upgrading is pretty painless unless your on a BES and don't have a remote connection to the server readily available. Other than that, I recommend a 4.5 upgrade. I haven't regretted it for a second and I'm on my 3rd or 4th 4.5 OS.