I came from BMW as well, from far enough back that BMW reliability was a certainty, not just legend. I'm still of the opinion that BMW's failures are largely predictable, where to my observation Ducati's are more varied and unpredictable. I also understand that parts availability can be less than timely. So far (6 months in), I have not experienced any of this. (NOS '16 MTS). There are things I'm watching for; my bike has a recall for the key fob. I bought understanding that dealer-performed mainenance is more than incrementally more expensive than on the BMW.
So, as another expatriate BMW rider to another, read up. This site is a great source. So is the Ducati area over on ADV rider. You probably need to take the opinions from each with a different grain of salt. But unlike buying most cars today, buying a European motorcycle (and with apologies, particularly a Ducati) is a leap of faith.
As to the MTS itself, it is somewhat lighter than the GS, a good bit lighter than an RT. But it's as tall in the saddle as a GS and seems to carry its weight higher. I notice this pushing it around, not while underway. The 1200 or 1260 engine is much more immediate than the boxer. There are more, finer points I could opine on, but we can all answer those questions for you as they come up.
HTH.