I recently moved my iBurst connection to my new offices while waiting for an ADSL installation. 4 months later and I'm still waiting.... (that is another blog / rant)
In the meantime I've been using my HSDPA HTC Touch Diamond to connect to the Internet from home. What a crock. I have seldom got more than 15KBs. This compared to the regular 100KBs achieved on iBurst.
Frankly I think there is too much contention on the cellphone networks and the advertised data speeds are impossible to achieve. Of course if you connect bigger and better aerials I am sure your speed improves exponentially. I am led to believe the stronger your signal, the higher priority your data requests achieve in cell contention algorithms.
Anyway, I could not take it anymore this weekend and rather than working in the office I bought another iBurst account.
UPDATE: Ok. Improve that: My office iBurst (downloading some stuff remotely) is bursting at 145KBs - with the wireless modem in a server room in the middle of the building - no external aerial!