Thing I love about the rack mounts is all the noise and vibes are behind you. Really makes for a pleasant ride. The center of gravity thing really is not noticeable. In our happy lil crowd here, the average rider weighs some where between 89 LBS and "Mother of Good, how do you buy cloths" and sits on the second highest point of the bicycle. Might matter in the Death race but tooling around, I never notice it. On top of all that is more comfortable with regular peddles and no tank. (my favorite thing about 2 smokes is the normal peddle width)
After the first time I rode one, the look grew on me like you wouldn't believe. #4 on my projects list is a rack mount on a step threw framed Point Beach. Is down the list from a pusher for most of the same reasons.
Just went out for a smoke and counted 4 MBs in various degrees of assembly. All in-frames, lol