I spent some time with the F210 yesterday and have some initial impressions.
PORTABILITY
As Don indicated, the top handle and slim profile work well for moving around the cab. It's much easier to carry than the 12/6 with side handles that I used to own. It could be a bit of a challenge for someone who is relatively short, given its height and weight.
SOUND
It sounds just like my F110. A giant F110. When I initially contacted Don to say I was considering either a second F110 or an F210, he suggested that an F210 would not only provide a single cab solution, which I prefer, but would have more relative output due to its volume. He was right. The low end of the F210 is huge and fabulous, which I don't believe would be achieved with 2 x F110s given the physical limits of the individual boxes.
I own two TecAmp Puma 500s, the original 2U Powersoft and the new 1U. Their tone is identical to me. The difference lies in the presentation of the tone - the 1U is tight while the 2U is softer and has a huge, pillowy low end. While I prefer the 1U with the F110, I had a gut feeling that the 2U would sound nice with the F210. Bingo! The huge sound of the F210 swallows up the 2U low end in a wonderful way. To me, the analogy of the F110/F210 is the same as the Puma 1U/2U - same tone profile, small and tight versus huge and full.
Don mentioned that the F210 is a great cab for Jazz and R&B. It's also a great rock cab IMO. I used my fretted Rob Allens, all with mag (no piezo) pickups and roundwounds. It stacks up against any rock cab I've ever used.
CHOICES, CHOICES
If you're looking for a single cab solution that will stack up against any 115 (or 410, IMO) the F210 can't be beat. If you're height or strength challenged or just prefer modularity, a 2 x F110 stack will still be a beautiful thing.