I don't have the G10 grips yet (I have some on order for a 228R that I recently purchased), but they are basically the same grips as the aluminum, just made out of G10. But the advantages of G10 is that it is lighter, and it acts as an insulator, so it lower hot or cold transmission between the gun and the user. Also the G10 grips will not wear the finish off like the anodizing on the aluminum. See this picture:
Toward the bottom of the grip you see white specks, those are the areas that the anodizing was worn off (this is my heavy use Sig 226). There is a bit more when you take a full side on picture, this picture minimizes how visible it is.
But OTOH the G10 grips will be slightly less resistant to getting gouged. It is virtually impossible to accidentally damage the aluminum grips by gouging it, the aluminum is too strong, but it is possible with the G10 grips, but it's still fairly hard to do.
Anyways it's a trade off, IMO G10 should be the way to go, but time will tell. I will be putting G10 grips on my carry Sig, and on my new training Sig (I'm a recent covert to XS Big Dot Sights so I am building a dedicated training 226 with Big Dots on them). If they work well I might even switch over all my Sigs that have aluminum grips on them.
Anyways I agree with Lone Haranguer, if you put the CTC grips on the classifieds here, and on Sig Forum you should get somewhere between $200-300, that should pay for new grips, a short trigger, and even some ammo depending on which grips you get.