My 2 cents
In my fifth year of daily carry now. I've carried (and still do on weekends) a Glock 22, Para Tac Four, Ruger P90, and now my everyday gun, a Smith 1911 Scandium. After getting tired of worrying whether my holster was poking out from under my jacket or other cover garment every time I raise my arm, and dealing with having to remove gun and holster when entering a place where a cover garment was obvious or would have to be removed, which involved removing the belt to get the holster off since walking around with an empty holster in plain view still raises eyebrows, etc. I settled on a Tucker Texas Heritage. It's all-leather, a tuckable IWB. In cool weather I don't bother to tuck since I'll always have a cover garment, and I don't have to worry about the nose of a .45 poking out. In warm weather I tuck it. The body side of a good IWB will have a tab or 'ear' extending above the mouth of the holster to keep the hammer, beavertail, and end of slide from chafing or being sweated on. With sharp grip checkering, the first week of summer wear without an undershirt can lead to discomfort, but it goes away afterward. Maybe the skin over my love handle gets tougher.
I can wear a dress shirt and tie with a full-size auto underneath with no problem. I can wear the gun all day and drive for hours. I can do yard work all day with it.
So I stay with IWB because it's so versatile.
My only complaint is the belt clips which, as you can see from the above photos, can be very conspicuous. I finally ordered some 1" wide 1/8" thick spring stock steel from Brownells. After a few attempts, I learned to shape it into belt clips roughly the same as the stock ones, then cut them down to about 3/8" wide or a little wider so they're about the same width as most belt loops on pants. Then I re-tempered them, gave the exposed surface a slightly rough, non-glare finish, and blued them. They are VERY inconspicuous now and they hold the gun just fine.
A good gun belt is key. Bulman Gunleather makes one that is fairly dressy, so I can wear it with office clothes without it screaming GUNBELT.
Friends who know I carry will usually have to pat me down to know whether it's there; my shirts tend to blouse over my belt loops a little because of my slim, trim, manly physique (I wish), giving better concealment.
No concealment method is perfect. I cannot deploy my gun as fast as I could with an OWB, no doubt about it. But I accept the tradeoff because with my IWB tuckable, I'm far more likely to have that gun on me when, God forbid, I need it.