LOADS of people use Aspire. They are extremely helpful. I wouldn't buy Chris King bits from anyone else.
Never had a problem. They once sent me the wrong spare part I wanted for my SS Chris King hubs. I rang them up, they apologied profusely, said they'd get the bit out straight away, and just to send the wrong bit back when I could.
Delivery can be up to a week (once waited 10 days for some Easton carbon bars, a one off though)