Indeed, I was not 100% satisfied with DD customer service when I have ordered before, but was able to get some anime BDs on nice prices from them. For this reason I have used PayPal at checkout, because if there is a problem, then I can issue a PP claim.
I have used Credit Card for previous purchases but even with that I did not get -$ after ordering...if there was a problem, the Customer Service sorted it out. The only problem was that sometimes different people handled the problem and they did not communicate with each other so sometimes it made it harder to fix the issue...but in the end, everything was fixed.
The disks I have ordered came in ordinary bubble envelope, because they were only normal BD releases, so I do not know how they ship expensive stuff like this, I will comment on this when my order arrived.
If the order gets lost during shipping, DD will issue a refund and I dont know about damage because so far my orders did not get damaged.
oh about damage...that is mostly the Postal Service's fault, I have received many orders from Amazon too that were slightly damaged.
In short, DeepDiscount is okay, however if you need to contact support because of an issue (like canceling an order), it will not be as easy like at Amazon or RightStuf.