ZVH's can be good but the general view on them is there is a LOT more £££ needs to be spent to get it to the same level as a CVH.

A lot of people also say the CVH revs a lot better. To properly build up a ZVH it also to be a proper job needs custom cranks etc.....pricey.

As for ZT's theres not much mention of them that ive heard. CVH all the way for me