I would have answered "Other" if it were an option because the truth is it depends.
I carry a P229 AIWB, but I think I might be able to pull off a P229 but I'm not sure (I don't have one). You reach a point, however, where too long a barrel digs into the crotch area when sitting. Conversely, however, too short of a barrel can cause stability problems necessitating a wedge of some kind to stabilize the pistol for a lot of people as body type can make a big difference.
When in doubt, however, the P229 is the quintessential carry choice for the compact classic P series (at least compared to a P226). I also like it because you can get a p229 barrel for it, and companies like Underwood usually load their self defense ammo using a 4" barrel as a blueprint in terms of managing velocity and penetration. It's not really a concern in my opinion, but if we're just being thorough with the options. The P229 was literally made for .40S&W (and is perfect for .357 SIG). It's more important for 9mm to squeeze out velocity as heavier bullets use mass more to their advantage which is why if you look at a diagram heavier bullets are usually (but not always) flatter for heavier bullets when comparing caliber performance to barrel length. Again, I don't think it's a big deal, but if we're teasing out differences, I think the P229 wins again when we're talking about concealed carry.
If you ever get it milled for a red dot, you won't even miss the sight radius either.
That said, I think there is often better aftermarket support for the P226, so there is that as well (e.g. grips). Having a Legion, however, I don't think that will be a concern and the P229 does fine with Hogue's offerings. The only mods you'll probably consider are with the trigger and the addition of a red dot like I mentioned.
Here's my P229 next to my Beretta PX4 Storm Compact Inox. For my the 4.25" barrel of my M&P is just a little too uncomfortable to carry this way, but that's with my body (I'm 5' 11").
The wedge is much more important for the Beretta which has a slide more similar to that of my Glock 26's than my Glock 19's, but I use wedges on all my guns anyway to point it away from myself.