Which BlackBerry is it? My Curve has the letters in exactly the same places as on a keyboard, and the shift and alt keys are close enough where you get used to it after a day or two. Some of the symbols are in odd places, though--it took me about a year to remember the @ key was Alt+P.
As for typing on it, I use the side and sometimes a bit of the pad of my thumbs to type. My speed goes way down if I use my nails. In fact, this is kind of gross/sad, but I'm a lot better at remembering to trim my nails in a timely fashion since I got my blackberry. Even a little bit of white showing on the nail is enough to get in my way and slow my typing.
You didn't ask for app recommendations, but if you use Facebook and Twitter, apply for the Socialscope beta now. There was a really long waiting list when I signed up, and there probably still is, but it's the best program out there for checking status on those two social sites. I've also found QuickLaunch to be a godsend. You can set QL to one of your side buttons, and then assign letter shortcuts to just about anything your phone can do.
As a few examples, I can hit B on the homescreen (turn off dial from homescreen in your options) to load up the browser, then click menu, then click bookmarks, then click Google Reader. Or, with QL, I can hit my right side key, then B, and that sends me straight to the site.
To text my brother, I can hit A for the address book, then type in the first few letters of his name, then hit the menu key, then click on send SMS. Or I can hit sidekey+C and it goes straight to our text history and I can type right from there.
If you're in to podcasts at all, PodTrapper is seriously worth the money.
And I'm not sure if Sprint allows it (Verizon only finally did a few weeks ago), but the Skype application is awesome.