I might as well weigh in also!
When we were thinking through this decision, we tried to focus on features that we felt would make transition to and maintenance of a live-aboard status workable for the two of us.
Carrying weight was the issue for livability, as well as really limited stand up interior living space in the Gem. Great for younger folks - less wonderful for us. We will miss the "one level" living of the Gem, but feel like access to the larger useable "living space" of our Irwin is a good trade off.
Underway comfort was a huge factor. We had the Gem out in several small craft advisories and frankly, while the boat
did great, we
got the crap pounded out of us. That's a function of the low bridge deck (every wave is a SLAM on the bottom) and the beam (14ft). Most likely this was a particular Chesapeake Bay issue, with the smaller period chop and power boat wakes. (When I did the delivery of s/v Felix with Dan we did open ocean from Cape May to Block Island and the Gem was a comfortable ride in pretty big swells.) A larger cat would not have those issues, and would have better cockpit seating
for underway. In fact, we're seeing lots of larger (38, 40, 46, 50 ft) cats on the Bay in the last year or so.
I was surprised and delighted at the feel of the water/wind when I took the helm of the Irwin. I had forgotten what fun it was to feel the wind in the sails and the responsiveness of the rudder/boat. Its the difference between a Cadillac ride and a sports car hugging the road. One's a smooth ride: the other's fun to drive!
Our ideal boat is a Voyage 44 or something similar. A cat that size would eliminate the underway and living space issues above, but add significant cost to the equation. Not going to happen with our budget.
So. We compromised. I'm deeply sad to see the Gem go, but focusing fiercely on making the Irwin a home, because getting out there is the whole point.