The flared magwell makes it less desirable for CC for me. I'll stick to the gen 3.
You don't like the gen 4? Just curious.
Gen 4 in OK but I don't think it was any improvement over the proven Gen 3. Gen 4 had some issues when they first came out with the recoil springs not being reliable with all loads. I think it's worked out now,but I know for certain the Gen 3 will run perfectly.
If I had hands large enough to need the grip increasing pieces,I would go for the Gen 4, but I like an even smaller grip. The very small reduction doesn't seem to be noticeable for me on the Gen 4 so that's no benefit.
I also think most of the Gen 3 triggers are less mushy than the 4's,and though you can work on either to get a good trigger,I think you can get a slightly better one if you start with a crisp Gen 3.