I been practicing with airsoft on regular basis for awhile now, and feel its a very worthwhile thing to have. There are ways to practice that you just cant do with a real gun, short of shooting each other for real.
I have to assume that those who state that the guns dont feel or work like the real thing have not spent much time with one, if at all. I have P229 gas guns that feel and work just like the real one in my holster, (actually, the airsofts fit perfectly into my holster and you cant tell the difference when its in there) and accuracy is actually very good at the ranges I wish to practice what it is I'm practicing, and my shots go exactly where I was looking or my my sights were when the gun goes off. The gun also cycles just like my real 229's, and while I dont get a true recoil impulse, I do still get one and the slide reacts just like the real thing.
Sights and trigger are very similar to the real thing. The only difference for me is, I'd like to figure out a way to put some old night sights on them, as thats really the only difference I see.
Over the years, I've tried to find something that allowed more realistic practice. I've been shot at and with pellets/bb's, wax, plastic, and rubber bullets, paintballs, you name it. Some things worked better than others, and up til airsoft gas guns showed up, the most realistic worked the best with real revolvers, as they usually functioned for more than one shot without you having to hand cycle them.
The biggest advantage here is, you can work on actually shooting each other and find out where your weakest with nothing more than a "sting" as the result of doing something wrong. Its enough of a sting, that you know you got it, and plenty enough to make sure you dont want it to happen again.
You might think your a pretty good shot, and clean up at the "games", but it all changes when the target shoots back, and is actively trying to make YOU the target.
Even if all you do is practice drawing and moving in your basement or house, you will gain much more of a benefit than if all you do is stand in a booth or box at the range and shoot paper. I can guarantee you will learn more about realistic shooting and that if you dont move quickly and aggressively, you will die. The last place you want to be, is "in the box".