As the earlier post noted, since the latest ROM update (really it was the earlier battery updated which is included in the latest ROM that did it for me) I have had no problems
at all.
Bluethooth works with my T68i every time and I have no problems connecting to the WiFi network at work and at home. No hard resets, no lost data and (thankfully, at least recently) no Active Sync problems.
I have three spare batteries and an external charger. Before the batteries became available (it took nearly 5 months) I constantly worried about running out of power, so things like WiFi were used sparingly. No I don't worry about anything and just flip in another battery when I get down around 20% or so.
Although the 5550 sparked my interest with the 128MB RAM and the claimed increased speed of WM2003, I may just wait to see what the 4000 series looks like. Hopefully, HP will just get it over with and do the right thing; 2200 form factor, 2 expansion slots, 128MB RAM, Bluetooth & WiFi.
But I am sure they will leave something out and make me wait a little longer. As long as I have my 5450 though, I will be patient.