I've had a good experience with AIM and InterOrdnance.
When I ordered from IO i wanted to get an excellant grade SKS, but she said they were out, so I ordered a M38. She called me back a few minutes later and said she was wrong, they did still have excellant grade SKSs, would I like to order one? IMO that is going the extra mile for customer service...
Century takes a while to set up your account. Took them 2 months to get me in their system.