We made the switch from popup to TT just a few years ago. But for us, the considerations were different than most families. It was becoming apparent that our young DS has autism. The setup/breakdown of our popup was beginning to be too difficult with having to keep up with him, too. We sold our popup in late 2010, but did not find a used TT until late summer 2013.
What we have found is that the ease of setup/breakdown of our TT allows us to take DS camping frequently. I take him 10 or 12 nights each year by myself, always one night at a time to our local state park. DW and I combined take him several times as well.
With our situation, the bottom line is that we would not be able to camp without our TT. DS plays in it occasionally in our back yard, we can pack and unpack from a weekend of camping pretty easily, and I can have the trailer set up and ready to go in about 15 minutes at the campsite. Breakdown is similar.
The costs of TT ownership are higher, the maintenance is a little more involved, etc., but the tradeoff for us is easier and more enjoyable camping, and just the fact that we can camp at all is huge to us.
This is not scientific research at all, but I see a lot of posts on these forums of people going from a popup to a TT, but only a few where they tried a TT and went back to a popup.
Only you can decide for yourself the benefits of each type of camper and how you want to camp. They are very different in many ways, so you will have to do some research, go spend some time in some TT units, evaluate your camping budget, and make the decision that you think is best for yourselves.
Good luck!