The V4 is truly a unique piece of horological art. The layout of the face is like that of the engine block of a car. It is a fascinating piece to just sit and observe as it's belts carry forth the energy of the watch and turns the gears from the escapement down to the second, minute and hour hand. I have never seen anything like it. Why belts? I guess because they can but why not? Will the belts stand the test of time? Don't know. TAG has a maintenance request of every 18 months for which the first few are free of charge. I am sure that it is so that they can monitor the wear and tear of the belts. The problem is, I am not sure how many owners will make this watch a daily wear so there may be a false sense of security by monitoring the watches in general circulation.
It is somewhat bulky to wear but it is not uncomfortable and sets nicely on my 6 1/4 inch wrist. My only criticism of the watch is the winding efficiency of the winding mass in the back. I can't call it a rotor as it does it's thing in the vertical plane only. I find that the watch should be powered up by the crown and the winding is continued by way of the mass. It is certainly notable when the mas clunks to the opposite side. It can be felt but it is fun to feel it and is an idle pleasure to feel it by rotating my wrist. The hands are not my favorite as they seem to be the same hands that are found on other TAGs but I have grown to like them.
My preference is the platinum version followed by the Ti version. Not a fan of the RG version (strange for me as I am a RG fan).
Hope this helps.
Mitch