I've had a Sidekick for a while. Unfortunately, I now have a Blackberry, per my employer's "request." They are terrible. If you own a Blackberry and think you've got a "real" phone, stop kidding yourself. Its a scam. If you are professionally able, switch to a different phone. Of course, my experiences come from dealing with T-Mobile, a company that has dropped about 15 notches in my opinion scale as each new horror of what living with this thing will mean becomes apparent. Your mileage may vary, but it probably won't.

1. With a Sidekick $20 a month covers unlimited internet and sms. They want $30 a month for "unlimited internet" for a blackberry. This doesn't include SMS. Unlimited SMS costs another $15... So thats $20 or $45 a MONTH for the SAME THING.
2. Apparently tmobile tries to charge you for AIM messages as if they were SMS messages. IE the "unlimited internet" doesn't apply to some internet services. Now I'm fucking down for federal network neutrality legislation. If you are selling me "unlimited internet" access, you better fucking be selling unlimited Internet access. Anything else is FRAUD.
3. The keyboard is too small and the keyboards keep getting smaller in newer phones.
4. There is no way to scroll sideways on the older phones.
5. You called BBSs in the late 1980s that had a more pleasant form UI than the one used for adding new contacts to the address book.
6. They are just now adding cameras. Its 2007.
7. Trying to download software over GPRS and having to restart every time you don't make it through the 30 minute process without a hiccup. Honestly, I haven't had to deal with something this stupid since Z-Modem was released.
8. They are charging your company a bunch of money to run this system that allows you to access your email from your cellphone. Its called IMAP over SSL, and its MUCH MUCH cheaper than a Blackberry Enterprise Server. In fact, ITS FREE.
9. IMAP over SSL is less likely to provide a backdoor through which someone can gain complete access to your corporate network. How often have you accessed your intranet server from your cellphone? I didn't think so.
10. tmo.blackberry.com... Worst email domain ever.
11. All your Internet access is proxied through your employer's servers!

The bottom line is the Paris Hiltons of the world ARE in fact smarter than your average account executive. They are buying more phone for less money. This isn't terribly suprising, but thats not how things are supposed to work.