I bought the Ricardo 3 year's ago. This is a brand new unit so I don't see any problem with this unit for many year's. The internal parts are in other Ricardo units so i don't see any problems with getting parts.
So why did I go for the Ricardo... This discussion you will find on this forum and other forums like the GT40 forum. But for me this is a new and modern unit with smooth shifting, can withstand a lot of power and they are cheap.
I looked at many different unit's and they cost 3 times as much for a unit with same spec and then I also had to do many mods to get the unit in.
ZF is a good box but with the engine I went for it's just to small and parts for the ZF is to expensive to change every year. I want to use the car without thinking of breaking the box. and parts are cheep in England where I bought the unit.