The reception in Vietnam is about on par with the rest of SE Asia. I had my 68 when there last year. In my time there, I thought reception was slightly better in HCMC than Hanoi. SMSing was really slow everywhere, even to another 68i in Nam, but that could have been delays from having to do an international roaming. The worst was up in Halong Bay, but that might be expected. Networks came and went on my 68i, but my g/f's was always a little more stable and picked things up better. Calls to and from other parts of SEAsia weren't as good as calling the US, oddly enough.
Some sms sent to Singapore and Vietnam didn't make it. I realize I was unlucky with that phone, but I had better reception in China on a T39.
I did see a big advertising market for SE phones there, moreso than Nokias. Hopefully, if you do go that route, you'll get one a little bit better than I had.
btw, not to make Vietnam's reception sound bad, I had troubles in Austria of about the same caliber with that phone, though it worked as well as it ever did in Munich. The biggest reception problem was in Phoenix and Albuquerque, which led me to switch to Nokia.
I've heard better things about the p800 and the 7650, though not enough to consider getting a new phone... yet.
