I've owned three VFR750's so far, and my current one which fronted a pack of pschos (friends) riding a Fireblade, SP-2, CBR600RR and R6 last Wednesday has done....
105,000 miles!!!
And of those 3 I've owned I have NEVER had to touch the engines!
I loved the ZXR to bits - but in the 3 years I owned that I had to work pretty damn hard to keep the thing running and on the road!
So I can't really think of a much better engine to slot in and forget about...