Here in the UK, I get a lot of my mail-order stuff from Silverprint (except film for which there are cheaper alternatives).
The only downside I have ever had from them is that they can be slow to dispatch. If they have evey thing you want in stock, fine - it will go out within 24 hours but, if they do not have an item in stock, they will tend to sit on the order for a few days while they get supplies in. In the last 6 months or so, they have now started phoning me back to tell me if an item is out of stock, so they have improved somewhat in that respect lately. In the past, before they started doing this, an order could arrive the next day, or 8 days later....
Other than that, I've never had a problem.
Probably best to tell them to contact you if anything is out of stock when you place the order. Obviously, I can't speak about their deliveries to overseas destinations.
Cheers, Bob.