Well my last bike was a 99 supersport 900, and i'm now on my 748. So i'll give this shot.
900 2valve aircooled vtwin is nice engine...with little work and gearing it makes midrange power like you wont believe. It is not pure performance bike, at roughly 70-75hp at the real wheel your not gonna win any Motogp's with it. However it make power in a deceptive way due to the nature of the twin. Lots of toqrue right now in most any gear.
1. Fun engine with alot of uniqueness and is very fun to ride.
2. Very easy to work on and service
3. The sound is killer with set of nice pipes..hell even stock.
5. grunt for the real world of corner carving
6. pretty lwo insurence cost, at least for me.
7. A bike that stands out from the crowd.
2. if you don't service your bike the dealors are Killer expensive and it needs valves adjustments every 6000 miles(checks actually you not need to adjsut anything)
3. Costly to replace broken parts, but this is true of any sportbike.
4. carbs, personally I'm new school and i don't like them that is only a con to me really, as with your f3 you are already used to them.
utlimatly if you go into buying ducati willing to learn what it takes to keep it up and running you will be fine, if you go in with mentality learned by japanese bikes(oil,gas, and forget it) you can run into big problems, that will cost a shit ton to fix.
If you get it grab haynes manuel first thing, that sucker is life saver, and pro-italia desmo valve adjustment dvd is great too.
personaly i say grab it up, i miss mine even though my 748 is faster, lighter handling, and generally(to me) more visually appealing bike there is something about the aircooled twins that is just so fun.