Well my boy,if you`re thinking about it the chances are you`ll do it.My Buell is only a humble X1 tuber not a hi tech fueller like your XB.
Performance the 749 is better,reliability I`d say the Ducati edges it to,I`ve only ever been let down by a Ducati once in well over 100000miles and that was a rectifer on a ten year old 888,I`ve only had the Buell a short while and it`s already sheared a engine mount
Handling........Mmmm the Ducati is more stable mid corner,but the Buell turns quicker.
I can service my Buell for under £40,you`ll do well to do the 749 for under £400.
The Buell takes me back 20 odd years to when no one was bothered about lap times,tyre compounds and getting their knee down,and the only people in one peice leathers were BMW riders,it`s just a hoot to ride.
I absolutely love riding the Buell,more than any other bike I`ve had,it`s not a particully good bike,but it does it for me
Like the Pieman says "very different tools for different purposes"