I just switched from a class c to a trailer. Apples to oranges IMHO. I agree with all of the above.
Here is some of my personal perspective from having made the switch recently. YMMV depending on the rig etc...
1. Yes. The class c was better for buffet traveling. Seeing lots and then moving on to see more.
2. Yes. The class c was more convenient for travel in terms of bathroom breaks and stopping quickly for a meal etc... With our new TT we have to find a larger spot to park, get out, let the slide out and then have lunch. Not a huge deal but frequently a bit of a pain for us compared to a 24 foot class c with no slides. You can't just "pull over anywhere" to eat, pee, or get gas.
3. Yes. The trailer has more living space in our case.
4. The trailer has (IMHO) a larger learning curve. I had never towed before so learning to hitch correctly, using a brake controller, and learning how to set up the Husky Centerline was new to us and required a lot of research and trial and error. Not so much for others of course. Backing in to sites is tricky at first but then with practice, you get it.
5. I do like having my truck at home with me. Great for trips to Costco, Ikea, and Home Depot. Throw the bikes in the back. No room for the trailer or the class c at home as we live in a townhome in LA. Also easier to do oil changes on the truck with it parked just outside as well as on the generator because it is in my garage, not in storage 20 miles away.
6. The new trailer and almost new truck was about half the cost of a similarly sized class c with like features.
7. Insurance is the same almost to the dollar on the class c and the TT. Adding the pickup makes the insurance more expensive by a long shot for us.
8. The TT and truck are over 40 feet. The class c was only 24.5 feet total. That creates tons of potential issues, especially in National Parks and when getting gas.
9. I mentioned a genset earlier. While having the portable generator at home is convenient, not having it at the push of a button and safely tucked below the class c is a bit of a pain at times especially when it is cold outside or raining. Also, it's a pain to move a larger portable genset that can run my AC. I thought I could just keep it in the truck but that's not always possible. Plus, now I have to travel with and sometimes need to store gas depending on where we are.
10. My trailer actually tows more easily than my class c drove. I had to really concentrate when I drove my class c. It handled like a crazy dog on a leash when it was windy or when trucks passed. When I tow the TT, I frequently forget it is behind me unless going up or down steep grades. The class c did handle hills better though.
Good luck with your journey. As was said, your intended purpose is the single most important factor.