They're two very different things, in two very different price ranges. It's just down to which one you prefer really.
I have both too. It's more like SHF = around 5.5 inches, S.I.C. = around 7 inches.
The S.I.C. has sturdy joints for a S.I.C. with easily to change parts. The cons about it is probably the black lines running through the eyes instead of the smooth with textured stripe in the original.
Outstanding point is the transformable gun/sword, articulated DecaDriver with a slot for the cards, and the cards all come in a hard plastic backing for you to stick on. (The cards are double_sided) I personally also love the aestheic of the clear pink parts, along with the details of the interiors on the legs. (They are removable).
The SHF has better articulation, especially around the shoulders, because the S.I.C. can't reach from one side to the other to show him opening the DecaBooker or whatever it's called. Cards are made of cardboard and you have to cut them out yourself, they are also single sided. The card holder is also openable, but doesn't have a nice indented area for the cards. If you want a figure that you're gonna play around or pose around a lot, you'd want to get the SHF, because they have strong ankle joints made of die-cast that helps weight it down for standing, and have overall strong joints that doesn't loosen up easily.
The con is the mold for the head, there are two horizontal seam lines across the face, one of the forehead, and one across the mouth. They didn't have this in the prototype photos.