Not the same guns, but I own all of those platforms. The Tokyo Marui ZET system GBBR is the probably the best performing and has the most aftermarket support. I wouldn't get the MK18 Mod 1 because the handguard and barrel nut is designed differently and requires different tools and difficult to remove if needing to replace hop-up parts. If you wanted the shorter outer barrel, get the CQBR.
Edit: Re-read your post and looks like you're also interested in the Tokyo Marui URGI GBBR. A friend of mine has one and has no complaints.