We started with a small (22-foot NASH) trailer, but then went to a TC. Trailer pros were: More space than a TC, could use the bed of the truck for stuff like chairs, etc., easy to unhook, leaving the campsite essentially reserved, and we could then take the truck exploring. Trailer cons were: Short trailer was not easy to back up, lower ground clearance when boondocking, it had a pull-out bed that needed to be taken down in the morning if you wanted to utilize much of the floorspace, and then pulled back out and the bed made up at night. The pull-out bed was also not as comfortable as a regular mattress. Also more limited as to where we could go as turning around on some of the back-roads we like was often nearly impossible. Finally, we couldn't take our Jeep or friend's boat when we went out, so the toys stayed at home. Switching to a TC, we found the following pros: Easy to take our toys with us, we could get into much more remote areas and rougher roads if we left the toys behind, better insulation than our trailer, larger fresh water tank in the trailer (54 gallons in the TC vs 35 in the trailer - bigger black and grey tanks as well), better ground clearance, comfortable bed that didn't need to be pulled out and made/remade every day, smaller volume makes it easier to heat so the propane lasts much longer in the winter, quality is better than the trailer was. TC cons: Harder to leave behind if we just want to take the truck somewhere without the camper, more steps to climb getting in (expected, but the greater ground clearance makes it worthwhile), the bed of the truck isn't available for miscellaneous stuff, so less storage space, a little less floor space inside, but we tend to spend most of our time outside anyway unless when the weather turns bad.
Finally, the TC just seems more "friendly" and "cosy" to us. Ultimately, what works better for us may not work for others. It all depends on where you want to go and what you want to do when you get there. As we get older, I suspect we'll cut back on the Jeeping and backroad exploring, and migrate towards more established campgrounds. At that point, I suspect we'll go back to a trailer (larger this time) or a small 5er. Good luck with your decision.
2012 GMC 3500 dually 4x4
2006 OKanagan 90W
2003 Jeep Rubicon, modified for off road performance