I don't own any M1 Carbines right now, but I've owned two in the past.
One of those was a Winchester and one was an Inland. Both of them were in fairly decent shape, both were pretty accurate and both were very reliable. I fired maybe 1500 out of one and 4 to 500 rounds out of the other, I never had a malfunction out of either one. I have no idea what some of the others are like, I've never even seen some of those manufacturers stamped on a M1 before. I should have never sold the Inland, but I did. The other I gave to my brother and he sold it somewhere along the way (thanks bro).
So for what it's worth I've had good experiences with those two, but that was 15 years ago.
I imagine that unless you're lucky enough to find some older guy who has one stashed in the back of his safe somewhere, that many of the original U.S.G.I. M1 carbines would be kind of shot out by now if they've been run pretty regularly. If they haven't and are in very good condition, they might be getting a little too valuable in the next couple of years to shoot the crap out of on a regular basis. But I think that they'd probably be okay for a couple hundred rounds every few years.
If I wanted to buy a M1 carbine that I was going to shoot extensively, I'd probably buy either a new Israeli Military Industries (IMI) or a new Kahr arms M1. Then I could shoot it as much as I wanted without worrying about losing any collectors value. I read a couple reports not to long ago where it compared those rifles against M1 carbine made in WWII and they actually did better as far as accuracy went.
Then again, if I wanted something to just take out now and then and if the history of the weapon was important to me, then I'd probably get another Winchester. They seemed like they were the best out of most of those, but I'm just going on the basis of my limited experience with them. Some M1 carbine collector who knows way more about them might say that one of the more obscure M1's was a little bit better and he may be right.
They're really fun guns, it's kind of like shooting a Ruger 10/22 with a little more pop to it.
That would be my 2 cents anyway.