When we returned from the TT this year it was our first voyage on the Manxman, then we sailed on it again for the Southern.
All 3 times we stopped in the bar/cafe area, even when they announced 999 passengers coming back from the TT there still seemed to be seats left!
The whole thing feels much more spacious than the Ben.
There are even seats/ settee type things in some of the wide corridors!