I transferred 3 .orgs a few months ago. The payment process was a bit annoying and caused a bunch of issues. I added all 3 domains to my cart and checked out, they charged my card, but didn't include the ICANN fees for the domains.
The first problem is that I was unable to log in to my account as it was suspended upon creation, so I had to contact them on chat and send them my id to unlock it.
The second problem is that they started the transfer a few hours after payment, but they attempted to charge 3 ICANN fees to my card at the same time. The first went through, the second were classed as duplicates by my bank and failed.
Then it became a mess of getting them to refund me the 2 failed transfers over chat and reordering each domain one by one again.
I don't think the system is very well designed, but I guess the transfer price isn't too bad.
Tip: The 30% off domains coupon is still working (I think it should have been expired a few months ago), when I checked yesterday: NSDOMAINS30