Engadget features an interview with Danger CEO Hank Nothhaft. Despite the fact that I don't love the new BlackBerry, RIM is clearly the leader in this category and will continue to be successful with their hardware for the short term as the OEM strategy evolves and competition with Good Technology forces both companies to make better products.
A few tidbits and unsubstantiated claims from Danger:
The people who are using IM on these devices are sending and receiving 110 instant messages a day. They're also doing 25 to 30 e-mails a day, and they're accessing 25 web pages a day. We also support SMS on this, and have a range of around 4 SMS messages a day.
I'm willing to accept the e-mail and SMS stats, but not the web pages and no way on the IM, especially since IM counts as a data charge on T-mobile. There are no statistics to either support or discount this claim, but anyone doing 100+ IM per day on T-Mobile