RIM's got two nice advantages to it:
(1) Employers often pay for the BB, and the data plan. You're getting access to a lot of users who wouldn't otherwise be customers in the smartphone arena.
(2) As the phones are already part of the business's primary operations, you have some nice opportunities to sell apps that integrate with the business.
Considering that RIM's product isn't even out the door yet, and the specific strengths RIM holds, it's not 100% comparable to the iOS & Android side. You've got the chance to provide something that isn't a (a) fart app; (b) casual game; (c) train schedule; or (d) local wrapper for the website.
Frankly, the superficial weaknesses of the form fillout and download procedure just aren't substantial. That's what, half a day? The next few months are gonna be in the APIs, and the next few years are gonna be in the customer base, app market, maintenance, and support of the app.