I am writing this from my N900. Did a test of 3g speeds btw N900 (tmobile) and my iPhone 3GS, which is on att, as I traveled from NJ to northern OH along interstates.

att has much better coverage and I was often getting 2 Mbs download. Tmo would only get 3g every once in a while and even then would top 900 kbs. Interestingly, upload would be higher on tmo than on att, about 340 kbs vs 280.

Of course, that has not much to do with the device. On the other hand, if its potential is limited by the only provider one can use it on in the US, that tends to reflect poorly on the device as well.

My other qualm is the email client. It is beyond poor, completely unusable. It takes about 30-45 sec to retrieve a message (imap) and then it often freezes. Email is a fairly essentiqal fumction so one would hope to have the basics done right the first time around. iPhone's email client is, on the other hand, quite robust and usable.

So, while I would love to replace iphone with N900, for everyday smartphone use iphone is still ahead by a large margin.