As Frank mentioned, all things are never equal, but all things do have a place.
IWB takes a little getting used to, but once you find your "sweet spot", and your body accepts it, things usually settle down, and you soon forget youre wearing it. You do have to give it a good chance though, and that may take a little while, and a good bit longer, if you dont wear the gun all the time, on a daily basis.
IWB is hands down, "the" best way to carry/conceal a full sized handgun on your belt. Because of that, I really dont see the point in bothering with the smaller guns, other than in a BUG capacity, but I know these days, people are into the smaller guns. I just usually find them harder to get a hold of quickly, and get into action.
I carry a couple of things as back ups in an ankle holster, although less and less anymore these days, in favor of my Smart Carry's. Ankle holsters can and do work well, if you are willing to find a brand that works for you, but they also have their challenges.
First, you need to find one that you can comfortably wear "all" day. The only way to really figure that out, is try them until you find one. Ive found, the "cheap" ones are a waste, and usually, literally, "a pain". Plan on spending a few bucks for a good one, and youre likely going to have to try a few. My favorite so far, is the Desantis "Leather Ankle Holster".
Ankle holsters tend to limit your choices, obviously, but you'd be surprised what you can get away with, with the right pants. The two handguns I normally use an ankle holster for, are S&W 642's, and Glock 26's. These days, I prefer the Glocks, and the J frames just come out for practice, to stay on top of them. The 26 just has a lot more pluses.
Like the IWB, you need to allow your body time to adjust to the gun/holster being there, and give it a good chance. At first, even the light guns really feel out of place, and throw you off a little, if nothing more than mentally, when you walk.
You also need to learn what to do with your legs when you sit. Youre safest bet is the "ankle cross", and with your holsterless leg over the leg with the gun. Depending on the length of your pant legs, your shoes/boots, and how low the gun is carried, you may or may not have issues with exposure, and you need to pay attention.
Getting the gun into action from an ankle holster also offers some challenges and requires some more thought and planning. Its definitely not something for a close proximity proposition. With practice, it can be quite quick to draw, but it puts you into a static draw only position. You either more, or you draw, you cant do both. Thats not a good thing.
If you feel you cant deal with a full, or larger sized handgun, I would also suggest you look into the Smart Carry holsters. Its sort of a "best of all worlds" holsters, and you really dont have to change anything about how you dress to pull off even fairly large guns. Some people, including the holsters maker, do carry full sized guns in them, but I dont find they work for me, with my lifestyle. I can do a Glock 26 without any problems though.
Concealment is very effective, its very comfortable, once you get used to it, and the draw is deceivingly quick and easy, even one handed. Sitting isnt a problem either.
