It was bad a couple of years ago (as in Hasbro didn't fill orders fully), but hasn't been at least since the start of ROTS.
I've found cases go in and out of stock fairly frequently on Newforce. I've always assumed that was their way of being cautious and verifying they were expecting enough stock to fill orders before opening themselves to new orders and possible disappointment. I watched this happen with the new VOTC (VSTC?) - I was going to order one day at work and they were sold out
but when I checked at home later they had some more up
I'm very happy with the service from Newforce.