I had a 4150 before switching to 6315. I did not use my 4150 for wifi connections excessively but I don’t think there is much of a difference. It works fine home where I use a wireless router to share my cable connection. It works outside too but I cant tell which one works better. Both should have the same kind of technology one would assume.
I just wanted to stop carrying a cell phone and a pocket pc all the time. The thing I miss most however is the speed. H4150 is still one of the most powerful ppc out there.
I would say don’t go for 6315 if:
1) Speed is a must,
2) If you make a lot of business calls and if you need a reliable phone. (there are still issues with the machine especially on missing calls while surfing via GPRS)
3) Size does matter! If you are used to carrying your 4150 in your pocket. (This thing is not a pocket device!)
4) If you are planning to use Bluetooth devices those require more than 1.0.* Bluetooth stack. (God knows who/when will provide an upgrade)
5) If you are used to not soft resetting your device more than once a day. (This issue is slightly fixed by the upgrade by T-Mobile but there are still unknown reasons for the frequent lock ups.)
Good luck,
