My 999 used to slip as I tried to set off at any sort of decent pace.A clean up and an open clutch cover sorted it.
I borrowed a 1000DS Monster while the 999 had its service and the clutch on that slipped badly.It had only done 1800 miles.My Multistrada,on the other hand,has done over 2k miles and the clutch has been problem free.I have heard tho,that the 'strada is fitted with alloy plates to quieten the clutch down.Might be worth considering.