Here was our thinking on things...
we tent camped when we were just married (often via motorcycle). I got tired of sleeping on the ground, being wet, not having running water and hot coffee, plus all the packing to go camping.
We found a $400 1966 Apache Raven popup - all canvas (real canvas) tent about the size inside of a dinette on a TT. Tiny. But it met the needs of getting off the ground,most things we needed stayed in the camper. It was stupid easy to tow (barely 5 feet wide and 800 lbs!). But being that small many things had to still be packed and go in the back of the van.
Along came kids and camping with grandpa - he's got a large coleman popup (with slide and all sorts of amenities). It's a step up from what we have (it's got a full kitchen, dinette, bathroom, but there's as much set up and tear down and if you pack up in the rain you get wet, the dew or rain you have to unpack/setup at home to dry out, etc. I see this as more work than fun and I don't want more work in my life.
Our kids are getting to the age they want to bring friends camping but not yet ready to tent it outside our camper. We have a son and daughter - bunking with us or each other is wearing thin as well.
So our needs are faster easier set up. less issues with rain (it always rains at some point, or threatens to). Seperate sleeping for each kid and us (this turned out to be the primary concern in choosing a TT). I wanted a fridge (i've grown very weary of replenishing ice) and a toilet that wasn't a 200 yard walk in the dark away in the middle of a rainy night.
The only downside is size - we just bought a 28' Grey Wolf TT - we need to now go buy something that can tow it and that will add 50% or more to our monthly gasoline bill year round (buying a vehicle just to tow costs about the same over a year's time but costs more to buy than just upgrading our current vehicle).
So there is a cost issue - vehicle, TT costs more and perhaps storage if you can't keep it at home. But in our opinion we'll camp twice as often, at least, and more comfortably with a TT than a popup. The hardest part now will the the drive to the campground instead of the wife and I 'disgreeing' over the setup of our popup.