Marmit 1:6 Stormtrooper just arrived. It is a FANTASTIC figure! I think this is indeed among the most accurate scaled Stormtrooper collectibles, very close to the Gentle Giant mini-bust IMO. The Marmit looks like a guy dressed up as Stormtrooper, which is quite awesome.
The Marmit armor has the rivets on sides, the bicep armor even has the "thumb print" found on the original armors, and the E-11 blaster, though maybe not as sharp as Sideshow's, has its own accurate parts like an M-19 scope (Sideshow's has M-38/M-40 scope) and the cylinders. The old Marmit body is better than the floppy Sideshow version. The helmet is simply fantastic and there is NO comparison with the Sideshow version. Of course you need to assemble this Marmit kit yourself (I got mine in an unopened box) and thus you need minimal skills to do so.
Sideshow version has its own pros though: sturdier material for armor, better E-11 blaster, more accurate thermal detonator (with the metal clips), more accurate cloth belt, a better way to attach the shoulder bells, chest armor and and especially the drop boxes, leather holster, joints on the feet. But overall the Marmit is still way ahead the Sideshow Stormtrooper in so many ways.
Here are some pics of my TK: