I haven't owned the Ducati, but I have three close friends who have.
One's had two in the last 4/5 years, no issues whatsoever and he loves the bike.
The other two, well, that's a different story. Both have had issues with the hydraulic clutch mechanisms. One lost the clutch completely and has to go everywhere with a can of fluid (back to the dealer's about 3 times before they sorted it; the other had issues on day 1 of a trip to the south of France (serviced about 2 days before he left). One of the three seems to drink oil at a rate that would make a 2-stroke blush.
Don't know whether this applies to the latest models, but the guy who lost his clutch also mentioned that there are some of the belts that need replacing at odd intervals (I think he said 15 and 18k, although this could be different). He decided to get them both done at the same time as a service (just before heading to the South of France), and that cost him £1,500. And they returned the bike with an oil leak that he wasn't happy with. He also complains the electrics / switches aren't the same quality as his last few bikes (2 Fireblades and a CBR600).
But they are quite pretty.
I expect to you, the GS / GSA is more of a known quantity. I've had 5 in the last 15 years and although stuff eventually goes wrong, my experience is that it's usually associated with mileage (I probably do about 25k each year on mine). Considering the mileage I do, I wouldn't consider the Ducati. If I did about 5-6k per year would this change my opinion? Probably not, as I've seen friends get frustrated by them on too many occasions.
Sure, GSs will suffer corrosion if you use them all year round in salty conditions and don't clean them off after each outing, but if you want the biking equivalent of the Duracell Bunny, it's the only viable option in my view.
Good luck with the purchase, be it Ducati or BMW. Or Honda...