If you like your P229, you probably won't like it as much after you get the
P226.
Ive had a number of both, and the 226 is still my favorite of the older P series. I never understood SIG's definition of "smaller" or "compact", as their smaller guns, really aren't, at least until you get into some of their newer "little" guns.
A P229 is fat and pudgy in comparison to the P226. The P226's grip is noticeably thinner and more comfortable, and the gun is only about a half inch or so longer than the P229, and more svelte.
The older W. German guns are nice, but their steel slides are rust prone and seem to be more prone to finish wear. I have and have had both, and they all shot and held up well to hard use.