Hey Rich,

Great question... I was in your exact position (voice device + sidekick looking to converge)... I went to a sidekick II, then switched to a blackberry.

Personally, I think the sidekick kicks the BB's butt in many categories:

1) email - MUCH better email client, and fully supports multiple accounts (BB will receive multiple accounts, but you can only send from one... two if you have BES)

2) web - both BB and Sidekick are equally slow... but I found the HTML transformation on the Sidekick was both a) better suited to the form factor and b) more reliable (my 7290 crashes on some HTML content pages, NOTE: I'm using the CIngular browser, waiting for 4.0 still...)

3) Yahoo! IM / AOL IM app integration - the apps perform extremely well and are very nicely integrated into the Sidekick experience. Verichat for the BB is a great app and does its job well, it just doesn't have the same polished feeling as Y!/AOL on the Sidekick.

I did a little summary in THIS THREAD that you might find useful.

and re: size, the BB is much smaller than the sidekick.

Ryan