been using PDAnet since december- works great - only complaint i have is all the frigging "updates" requiring update to both the phone's app and the software on the computer
be careful on your useage though - some have said there's a 5GB download limit (per billing period) before Tmo will throttle your connection back to EDGE speeds (from 3G) for the remainder of that billing period
i've watched my data downloads on my Tmo account page and have gone past 5GB 4 times (usually in the 6GB range) and haven't found my connection slowed down, but i always use it in the evenings to browse the web on the couch with my laptop
a poster in another thread, said he used to work for one of the big carriers, and that was was critical was not busting the upper limit during peak times, ie during normal workday hours, so that may be why i didn't see any throttling back on my useage
suspect my useage will go way up when the samsung galaxy s is finally released and full HSPA svc is deployed here in my area