First, thanks to DubK toys for this set. You rock! DubK toys here https://www.facebook.com/DubKtoys Words cannot do justice to this figure. Attaches simply. You can't use it with the Zenith Forge kit, as they both use the same connector at the top. I didn't try the 'g1 mode' with the dino hands as then you lose the 5mm holes in the wings. Ignore the scratches in the 'wings' of robot mode [over his left shoulder]. I started sanding it down to paint but then realized I should do the comparison review first. Pros: It [like the ZF kit] also fixes the issue of the shoulders rotating in and out. Very nice! The gun is nice, but gray. I'd prefer it in black, going to paint my kits [1x g1 colors, 2x g2 colors]. I prefer it to the ArtTek gun simply because the barrels are closer together like a real gun. But the ArtTek has a very nice color to it, so if you're not going to paint it, the ArtTek gun has the more accurate coloration out of the box. G1 style wings and bulk! Yay! Cons Gun is a little loose in hand, but I fixed that with future polish. Also the light up feature in robot mode is gone. The dino mouth won't open. EDIT: Might just be my set, as others can still use the light up chest. You just pull the head out a little more and it will work. Now for pics! Box, front and back. Meh. From the front. He gets his bulk, and it looks more G1 Top view, not too distracting, works well with the shape. Back view, you can see it fits in nicely and it holds the arms in place. Dino side view. Fills in the chest, but also gives it more of a shape that is G1 style. Very nice! On to the ZF comparison. I apologize that I don't have another regular FoC Grimlock to compare it to. My other is a G1 style grimlock [darker gray] and then I have a G2 grim in the works. This custom is from the FrenzyRumble custom class. Also the ZF kit is also custom painted, sorry. Front view. You can see the wings are the difference. Back view. You can see the IF kit is nicer in how it fills in the hole, and the dino head doesn't need to just hang there. Both fix the shoulders from flopping around, but the IF one does it better. It still is easy to put the arms back in for when you tf it into dino mode. Back view of the connection points. The ZF kit uses the screw-hole and the top area, whereas the IF only uses the top. That's why you can only use one of the two kits, at least to fill the back. And this is how it looks from underneath. You can see how much more the IF kit fills in. Aaand finally side view. You can't really tell much of the ZF kit from the side, but you can notice the IF kit right away. So here is the question, ZF or IF? If you just want a chest filler, IF hands down. It does a better job and makes it look more G1. It also gives you a G1 gun. It looks better in both dino and robot mode. However, the other parts of the ZF kit are great. The sword, shield, and head especially are amazing, though the head breaks easily. The ZF filler leaves a bit to be desired though sadly. Put it this way, Zenith Forge = FoC Grimlock, as FoC Grimlock doesn't have the wings. Iron Factory = G1 Grimlock. So pick which one you want it to be closer to. Price wise, the IF set is cheaper. That's all folks! Questions/Comments welcome!