The stainless is 6oz heavier, lacks the trigger work the Legion has as well as the X-Ray sights that I personally like quite a bit. They appear to have the same MSRP so street prices should be similar. That being said I prefer the Legion its my favorite double stack 9mm.
Picked up a "new to me" P229 stainless elite from the great people over at South County Guns a few months ago. It is now my favorite range gun. Had a chance to shoot my Elite side by side with a P229 Legion at the range a few weeks back and honestly couldn't tell much difference between the short reset trigger in my Elite and the Gray Guns trigger in the Legion. I'm sure our more skilled shooters here could pick up on the subtle differences though. The stainless looks awesome with either the stock rosewood grips or the E2 grips I put on her. Both are wonderful guns and I dont think you can go wrong wih either choice.