I carry a Sig P228, which is basically a P220 with a barrel about a half inch shorter. To be fair, it is a double stack 9mm as opposed to a single stack .45, but I find that the dimensions and weight feel similar when held in the hand (both my father and a friend carry a 220, albeit not full time).
In my opinion, the best gun for CCW is the one that fits you and you shoot best. If you like the 220 and shoot well with it, DEFINITELY pick one up. They are great guns. I find that the key to carrying one comfortably is a good belt and holster. I'd take a look at a Belt Man or Wilderness Instructor belt and a Crossbreed Supertuck. With this combination, I can usually conceal fairly well in shorts and a tshirt, though I usually wear a button down shirt that is a bit thicker when I carry. Just a bit more to help cover the gun.
The 220 is probably a tad bit thinner than the 228, so that would be in your favor. You could also look into getting the new grips that Sig is making (I think "e2"?) which are a bit thinner.