That keyboard was excellent and the slider mechanism was solid too! A lot of the later pkb phones don't have a dedicated number row. And I really miss the physical Home and Back buttons, even pkb keyboard don't have those these days. My only complaint is about the trackball. It was ok for some things but not accurate enough and got flakier with use.
I also loved early-Android UI. The modern stuff might be smooth but ergonomically it's crap. For me the G1 represents a golden age, I am sad that I gave it away.