If you can manage to back up your personal data in one way or another (my contacts and calendar are all synced from the web) there's really no reason you shouldn't give it a spin.

Portrait desktop is in my view the #1 feature / function, but the e-mail app might begin to crash a lot. My crashes always happen in the background, though so its never erased an e-mail I'm writing, for example.

Give it a go! Just read the instructions well before actually doing the installation: http://wiki.maemo.org/Community_SSU#Installation

And even more important page: http://wiki.maemo.org/Community_SSU/Installation_FAQ