I have a cm2 base and own the F18, Warthdog and CM2 grip as well...
I ended up using the CM2 grip for everything, despite not being "metal" I dont regret it a all, it is a superbe grip with plently of buttons, more than the F18 and Warthdog...plus it has a lever brake analogue axis which is percect for wheel brakes with my VKB MKIV rudder.
The F18 is not ergonomic at all, very uncofortable , the lever behind it is so short that is basically usless.