I just went down to my shed and measured the sitting head room in my 2012 Legacy. The boat is fitted with a full set of factory cushions and these headroom measurements are from the top surface of the uncompressed cushions to the cabin ceiling.
The side berth headroom is 30 inches.
We have the two infills and cushions to cover the foot well to extend the sleeping area, and using one of these as a backrest, the other as a seat and sitting amidships, legs stretched out toiwards the companionway is the most comfortable sitting position on the boat. The headroom here is 34 inches and I can sit here very comfortably with full sitting headroom.
From the floor to the cabin top, in the centre of the boat, is 40 inches.
Sitting on the side berths I have to lounge back a bit, I use the infill cushions as back rests and that setup is pretty comfortable and two people can sit around in the cabin at the same time.
It was mentioned above that the berths are a bit tight for leg room, they are, but most of your body remains out in the cabin, only the lower legs have to go up tunnels. The bunk infills are in my opinion a must have, they turn the entire cabin floor into a sleeping platform the full width of the hull. Using them, if you are cruising alone, it is possible to sleep diagonally across the cabin and not have to put your legs up the quarterberth tunnels at all.
Look, the Legacy cabin is small but cosy. I regularly sleep on mine, sometimes my wife accompanies me, and there is ample room for two to sleep comfortably and room for two to lounge around and read or listen to music and eat chocolate etc.
The Legacy cabin is big enough for me, I am six feet tall and weigh about 200 pounds, anyone smaller will have no trouble. Anyone much over six feet will probably find it all a bit of a squeeze.