Just consolidated my PDA and cell phone with the Siemens SX66 and it has already been replaced once.
The bluetooth ceased working and then it began requiring eith a soft reset or a hard one (battery removal), the latter requiring me to rename the unit when I attempted to synchronize it.
Cingular sent me a HP unit as a replacement but fortunately my local dealer had a Siemens SX66 in stock and I'm now using it.
This is the third day for it and this morning, in attempting to make a phone call, had to do a third soft reset (actually I took it to my dealer after attempting to call him and it locked up on the calling screen -- and didn't make the call -- and the dealer removed the battery. It's working now; only I don't want to have to do a reset daily!
Am also having difficulty with signal consistency at my home -- not a problem until this unit. Was told that when you combine a PDA and cell phone you have to give up some phone capability but also was told that in July the signal problem should be resolved with new towers.
I can, at least, swap the sim card to my older candy bar Nokia and have no signal problem.
Also have noticed that the reset sometimes caused my contacts to be listed separately for each number for the same person (home, work and cell) rather than remaining combined, requiring me to go back into it and cut and paste back into one listing per contact.
Will see if this second one will work okay. Was told by the dealer that it took getting a third one (second replacement) for one customer while three others weren't having problems.
I hope this helps you.
Ron White