All the time. They supply downloadable templates and deliver in plain packaging direct to the client with a separate invoice to you.
After purchase you can upload your artwork and after a minute or so download a proof for confirmation.
The greetings cards are 350-450gsm card.
Business cards are 450gsm. At their prices it's not worth printing my own.
They will send a sample pack on request.
Never had a problem and the clients are delighted with the speed, quality and turnaround time.