First let me say that these are both great boats. It was very eye-opening to cruise for 5 weeks with our CD-25 and Brent and Dixie's TC255... they are very different animals. They could definitely go faster in chop than we could (comfortably). The fuel usage differences weren't as great as I thought - it seemed that we were maybe 10-15% less fuel to cover the same miles. Our boat pounded much less with any wave action at anchor. They have storage space that seems never-ending compared to our boat. Their cabin floor is higher than ours (and my head and I appreciated their taller cabin door). It is certainly possible to cruise these boats together, with some compromising on both parts. In retrospect, I think we each bought the right boat for our individual cruising styles.
Now, to get to some of your specific questions:
* Payload: the TC seems that it will handle more, but both boats feel it when you load 'em up. Lighter may be better, but neither of us are minimalists. :wink:
* Sleeping arrangements: You have a berth up front and the dinette. Nothing magical about the space of either. I understand that there are folks who routinely sleep 3 or 4 on these boats, but they are really designed for a couple (IMHO). You can make most anything work, but (for us) having to convert the dinette every night would get old fast. And, those same 4 people have to eat (usually at the same time)... the forward seat of the CD-25 is wider than the TC255, but either is going to be a crowd with 4 at that dinette.
* Speed: The TC255 is MUCH faster than the CD-25. But, we could cruise slowly more comfortably and economically (at displacement speeds). To run together, we ran faster than our usual and they ran slower than their usual. So, it kinda depends on your cruising style for which one is better here.
* Skinny water: Either will do fine down to about 2 1/2 feet... slowly and with the engine(s) tilted up. This ability gave us more options when it came time to find good places to anchor. I'd call this one a draw.
* Ease of loading at boat ramps: We didn't launch/load together, but the bottom of the CD-25 sits closer to the road on the trailer (since it can sit between the fenders instead of over them). I'd give this one to the CD-25. We think this boat is a piece of cake to launch/retrieve; about 1000 pounds less all up, too.
* Rough weather handling: Both are good. The CD-25 will have to slow down sooner than the TC255, but when things get really snotty they are both down to displacement speeds.
Now for some opinion: I would go stark raving mad with more than a couple on these boats for an extended time. Certainly, with a couple small kids, it would be easier than traveling with another full-size couple... but eventually those kids are going to get bigger. Hey, you could take the family camping in a 4 seat econobox, but you're going to be more comfortable (and less on each others' nerves) in a full-size van. I understand the manufacturers' marketing hype for more "berths", but just because you could, it doesn't mean everyone should. Obviously, to keep harmony in the family, lots of time on-shore is going to make life easier. Now, keep in mind that we have no grandkids (and no real prospects for such on the horizon), but I'm guessing my opinion on space would likely change if our daughter and son-in-law ever decide to bless us with a grandkid. :wink Still, there is the concern of where to put everybody, their stuff, potty/shower time, privacy, etc, etc.
I have no idea where you'd put 4 kayaks and/or bicycles on either of these boats. We carry our dinghy on top, and feel we don't really have room for even a couple folding bikes. We'd need to learn to be more like El and Bill or get a bigger boat.
$$$-wise, similarly equipped, the TC255 is going to be $30k (+/-) more than the CD-25.
Good luck with your decisions.
Best wishes,
Jim B.