I would like a Gen 4...but not until they work out the bugs.
I would give it another 6 months. I don't want to go through another spring change, then an ejector change, then an extractor change, as they try to figure out what they f**ked up.
Some run fine. Some don't. Most people who tell you "mine runs fine" haven't shot their enough to know. They get a few hundred rounds through it and declare it flawless.
In many cases, the problems show up around 4000 rounds, by which point the gun has loosened up a bit. These problems have not consistently been fixed by changing the RSA.
I am looking forward to a Gen 4. When they've got them figured out. Not yet.