Attempting to have two bedrooms in a 36-foot boat causes a lot (too much in my opinion) of compromise.
Well, it works great on a GB36 Classic. Forward V-berth has two berths that are just about seven feet long, a head, and on the post-1988 boats (when they made new, slightly larger molds for the 36 and 42), a shower. Two stowage drawers under each berth with a bigger stowage compartment under them. And a good size hanging closet. All the guests we've had on board have loved the forward stateroom even though on our pre-88 boat the head is compartment is considerably smaller than on the later boats.
The aft cabin of our boat has a head, shower, a full queen-size berth, 9 big stowage drawers, shelves, plus a very large hanging closet with more stowage space on top of it. The queen berth is a relatively rare configuration on a GB36. The more common arrangement is a double berth to starboard and a single berth to port with big drawers under both.
In addition, the salon table and L-settee in the main cabin can be converted to a double berth.
The great thing about this configuration is that the people in the fore and aft cabins are completely independent of each other, with their own closets, drawers, and head compartment. So someone can get up, go up into the main cabin, make coffee, read, go for a walk, whatever, without disturbing the people in the other cabin.
It's a terrific use of space in a boat that doesn't look like a box, and was one of the deciding factors, after chartering one, that led us to select the GB36 for our own boat. The 42 takes all these features and makes them more spacious.
Were we to change boats it would be a real toss-up between another tri-cabin and a Europa. The Europa offers the covered side and aft decks which in the this climate are a real benefit. But, at least in the smaller sizes, you only have the forward stateroom. Guests have to sleep in the main cabin and that's a hassle to make up and stow the berth, plus everyone has to use the one head, and so on. For just two people the Europa is great.
When you get into a boat like the GB46 Europa or a Fleming 55 you can have two or three staterooms up forward so nobody has to sleep in the main cabin. Some models of the GB42 Europa also have two forward staterooms, so the need to put people in the main cabin goes away.
After taking longer (2 and 3 week) cruises with guests from Europe or here on board, were we in the position of having to select another 35 to 42 foot boat, we would most likely stay with the tri-cabin configuration instead of the Euorpa or pilothouse configuration simply because having two decent size and very liveable staterooms separated by a large main cabin makes life on board so much easier for both couples.