Satisfied T120 owner.
It's... interesting.
First six months of ownership I thought "Wow, it's an all round great bike." because you can ride it naked as is, throw a windshield and givi cases on it if you feel like it. It's practical for in the city as well as on the highway if you add some protection. Liquid cooling in the summer. Mine came with factory heated grips for the colder months. Insurance is pretty cheap by Toronto standards (I pay under $730ish/yr for 1200cc, not bad...)
Next six months I thought "But is it really perfect at anything?" because... it's not. My Husqvarna Svartpilen 801 is so much better in the city. My Moto Guzzi V7 has with 104,000 km has way more character. I'd take one of my BMWs to tour with they're already set up for the jobs. My Vespa is better at parking on the sidewalks and not getting a ticket... So where tf does this 1200cc Bonneville actually fit?
And for this past season, while a concussion has kept me grounded to the city and short rides only, no more touring until my head clears up I think I figured it out. It's the perfect one-bike-garage bike. Because it can do whatever you throw at it. It's not perfect at anything, but it's great enough at anything, that you kind of forgive it. It feels more modern japanese than retro when you ride it, but it makes so much gobs of torque that it's easy to forgive.
And that's probably why I might sell mine next year. Not because there's anything wrong with the T120 at all. It really is a great bike... but if I keep the Svartpilen 801 and something I could tour on/take highways better on... than... the T120 just overlaps with my other toys...
So since you mentioned the Speed Twin would be a spare bike for you, maybe think about what your current bike is, and where/whether or not, this one fits in.