you mean in Vietnam or returning. Both were fine. We left again recently at about 45 days into our second 60 day stay to attend a conference in a neighbouring country and came back 5 days later and got a new 60 day stamp but we are leaving after 35 days anyway so not issue. The immigration person on return into BKK did ask when we were leaving but that was all. We are going to apply for the DTV next time we leave
I bought 2 pairs last year, cost was about the same as Australia and one pair broke 3 months later. Only one experience so perhaps I just chose the wrong place.