I had better experience with British shop. I bought from them once and got everything in order in a two weeks. From Italy I was waiting part of my order for two or so months because they was busy to find the books that shows on their online store available that time. But they did responded on my messages and finally we figured it out and I bought something else, that was available.
My worst experience with US Shang Shung online store - my first order was OK, not so prompt like from UK, but I did received the items, but my two attempts later was without any result, I tried to bought one of CD (Trekcho teachings in mp3) and both times got nothing. First time they did returned my Paypal payment back, the second time I had to force it back myself - nobody did responded to me during a month or two. But I don't want to blame anyone because I am undestanding that most of people working there are maybe volunteers..
So my advice - go use Paypal and order from UK web store. Or drop them a message with a list of what you want and if they'll respond - go buy from them.