I've had the Storm for the past year and have not used the Storm2, or for that matter never used an iPhone for more than a few minutes, so not sure how valuable this information is, but these are my thoughts:
If you really like the iPhone, you will probably not like the Storm2. The best analogy I can give the Storm/Storm2 is it's a business man trying to be hip and cool. It gets the business end of things done well (email rocks, it multitasks 3rd party apps, you can put apps on it whether RIM approves them or not, you can tether, and it's pretty darn reliable), but doesn't do hip and cool well (multimedia is ok, camera and video are good though, not as many cool and fun apps as iPhone, web browser plain sucks).
Web browser they are working on, supposedly currently in the process of developing a webkit based browser for the BB platforms finally.
There are really only two big complaints I have about my Storm and that is not enough memory (Storm2 doubles this), and the typing is mediocre (Storm2 has improved significantly, but without trying it I'm not sure if it's almost as good as physical significance).
But bottom line, it's a different beast than the iPhone, it doesn't have near the application support, and it's just one of a long line of BlackBerrys that are not touchscreen so the amount of *good* application support will probably always lag some. But for business use, I still would pick a BB as my primary choice.
That all said, I'm seriously looking at that Droid or a successor in the Android space when my contract is up next year, now that I don't need my personal phone for primary business usage (I have another BB that is job supplied for that now).