For those of you have bought the Gamesmaster presents issue on the Sonic 20th anniversary then you're not exactly missing out on too much. It's basically a cut down of that with some minor alterations.
That said, there is some nice additions to the magazine too with Mario on side and Sonic on the other.
A nice and interesting 4 page article on Sonic Xtreme, a section discussing the early development of Sonic 1. You also receive some generic Classic Sonic 3 stickers of sprites and two very large double sided posters of Mario and Sonic respectively. Was very miffed at the fact that there was no article on Sonic 4: Episode 2 though.
Here's some shots of the mag in spoilers because
Also my camerawork is awzums!
EDIT: pictures fixed.