It's always fun ...
to watch everyone gyrate to show why their Uber-gun is better
My Uber gun right now is the USP 9 with LEM trigger. I think the USP and SIG are neck and neck for ease of us as far as the controls are concerned... As long as you're shooting right handed, which I should do more often
(FWIW, I think the Beretta 92 controls work best for me). I like the LEM, no levers, no fumbling around; it's just ready to shoot.
dropping the slide is a breeze thanks to the hard to miss slide release lever - in the event that the slide doesn't go forward when I put the magazine in...
The gun fits my hands well, I practice with it a lot, and I think that I got my money's worth.
In selecting this gun, I checked out Glock, Walther p99, and Sig. I didn't factor $$ into the equation as such as I wanted a comparison that wasn't financially driven. I shot all of the candidates but the p99, which I was impressed enough with after dry-firing it.
2 things moved down the p99 for me - the slide release lever, and the (then) lack of availability of inexpensive standard caps.
The sig controls don't work well for me. Accurate enough though. One other gripe with the 226's I've shot - the hatefully heavy double action trigger pull. The controls were my real concern.
The Glock didn't feel better or worse in my hands, but again, I moved it down on the list due to the slide release. Trigger pull wasn't bad, but not as good as the p99, imo...
The USP had a very easy to manipulate slide lever, and I had the gun converted to the LEM trigger. - This is a somewhat neat feature of the USP. If you don't like the double action Single action w/ safety, like it comes stock, you can have HK change the operating configuration for you. It can be converted to DA / SA decocker only, DAO, SAO, or LEM trigger operation.
My evaluation simply moved the USP up on the 'to buy' list faster than the other pistols, eventually, I'll probably have at least 2 of those above.
When you're selecting from basically top line, name brand manufacturer pistols, it really comes down to brass tacks. You mentioned this will be your 1st handgun, so ...
<jumps up on soapbox>
Get a .22 ! Ruger, Browning, S&W, Beretta... I'm sure many more... all make good quality, easy to shoot .22 pistols which are incredibly accurate, easy and fun to shoot. Not to mention CHEAP! One of these fine pistols is probably one of the best investments you can make in pursuit of good shooting.
</hops down off soapbox>
All of the pistols you have listed have good reputations. It's been my experience among handgun buyers that most have at least an inclination where they want to go, and want someone to help them "justify" going there. It's got to really come down to how well the gun shoots for you. You should have at least one range session with each before making up your mind. You can always buy that .22 while you're still undecided
When you have that list narrowed down to 2 firearms, stop torturing yourself, and buy both. It makes the decision easier.