Anime Cels World is good.  Quick to respond with 
availability and total cost.  Quick to send the 
cels (typically the next day) when the money 
arrives.  The cels I have bought have always been 
carefully packaged (in a celbox, inside more 
packaging) and arrived intact.

He's also good about emailing to notify you the 
day your money order arrives, and that's when 
he'll tell you the shipping date.  I know it 
stresses people out immensely to not get 
confirmation of their money arriving!