I have recently joined rebtel bandwagon but Himtel is not bad. They have one of the better customer service I have seen with any company (US or Nepali). I hated their "refill" your card scheme, which took forever to refill (and I couldn't even use it later for some reason). But I know if you have problem they will help you out. If I have problems with Rebtel (they are not without any either) I will use Himtel.