That existing valve is problematic, so it's good that you're thinking of replacing it. IT is cheap, and builders like them, but it is nowhere near quality!
The thing is held on with spring loaded spikes. You can push it on, but you can't easily pull it off. If you scratch the pipe up while pulling it off, a compression valve may not seal, nor will another that uses an o-ring, like the one you have. If you have something like a Dremel tool, you might cut a thin slot in it parallel with the pipe, then break off the plastic. You could then probably cut off the metal ring holding it in place. If the pipe isn't all scratched up, it's easy to install a compression valve...just takes two wrenches...one on the body of the valve to keep it from moving, and the second one on the nut which you tighten. If it isn't scratched up badly, a quick buff with some emery cloth or fine sandpaper, and the compression valve should seal. WOrst case, it's horrible, and then the best would be to solder a valve in place.