There really isnt any difference at all. SIG has funny ideas as to what "compact" is. The difference between the P229 and P226 is about 1/2" and the P229 is a little fatter.......there really isn't any difference in carry that I can tell.
This is sort of a problem with SIG's. Most of their guns are very similar in size, but perceptions seem to vary greatly.It just seems stubby I guess.
I have P6's and P229's. While the P6 is a single stack, and the P229 a double stack, I really notice little difference in the feel of the grip. Nothing like what you'd expect. I'd be willing to bet, you'd have a hard time telling which was which if placed in your hand and asked to identify them sight unseen.It's the same, looking from the side, as a P229, but it has a narrow grip with a single stack magazine.