Bad:
Expensive
Heavy
Complicated
Valves
Loud if derestricted
Soft Power
Takes adaptation coming off of a two stroke
You don't get to play with jetting and premix
Japanese, not Euro
YOU CANT RIDE THE VINTAGE CLASS ON IT
I would think the last one would be a deal breaker for you Jorge.
None of the above stuff really matters. But they are different than the typical two stroke. It will just take a few rides to get used to it. There are plenty around, just ride one and see if you like it. I don't know of anyone who has had any trouble with them. Condron probably has the most and hardest hours on his around here. I don't think the valves have even moved on his yet. I don't care for the guys who remove all the exhaust restrictors, it does give them a bark, when they do that.
I do know of a Repsol Replica that might be for sale. Mint, low hours by an Intermediate, but it won't be cheap and I'm not sure if he really wants to get rid of it.