For me (currently have a 4.2 Sea Spray Cc pontoon) it depends on the size of boat you want and what you do most in that boat.
Where in the country do you live? Im in Auckland, so we get a fair bit of decent weather as well as crap days.
Are you planning on long trips? Overnight? Out wide?
Small boat? Then the Cc will give you a heck of a lot more room, it just needs to be planned out well and have enough storage spaces.
med - large 5.5mt + then id be happy with a cabin, its warmer, drier and more sheltered, and being at that size allows decent fishing space in the rear.
Id agree with others above, at times I do wish I had a cabin (only on the crap days) but most of the time I love having the ability to fish all around.