I've bought one. It arrived more or less on time from Hong Kong but I didn't have to pay any extra charges. My expectations were low but I'm very impressed so far. The is a really good review on Techradar. It seems to be a slightly updated and kogan badged version of phones you can get off the web from China.
Both sim cards and a 32gb SD card work fine. It runs Android 4.0.4 which also works well. I like the 5 inch screen. Screen quality is similar to what you would have expected on a smartphone a couple of years ago, so not a galaxy note II. GPS seems to work OK. It can occasionally be a little slow if lots of apps are running but no worse than my iPhone. The camera is very poor though. Phone quality is much better than my iPhone so far.
I've loaded lots of my favourite apps and they all seem to work OK. I'll see what it is like in a couple of months but if you want a cheap dual sim contract free 5 inch smartphone you can't go wrong for £120.