I have only ever bought one DVD boxset from there, which was a bargain.. I didn't feel their prices were as good as on Amazon.. It didn't help that they didn't have an online shop.
I've bought a couple of things there but thought that they were generally overpriced. Worth a quick look now though if they are selling stuff off in a sale.
Our Silverscreen is rubbish. We have a big Fopp, a huge Virgin, and a small HMV all nearby and they (especially Fopp) almost always beat prices in Silverscreen. Whenever I'm buying DVRAB, I price shop but I'm yet to find a bargain in Silverscreen.