Fairly smooth actually. First 6 minutes were spent refreshing to get in. Then logged into my Oculus account and filled in my CC#. Took 5 tries at the "complete" button but then it confirmed. I've received a email saying my unitl will ship March 28th. Try just going to your basket and checking out. It might just not want to let you add more than 1 to the basket.
I see. Hmm no it definitely says Ive already preordered and wont let me go past the shipping details let alone payment. I guess I'll wait and see after a bit, make a sandwich Im starvin.