The major differences are 5th wheels tow better than bumper pull travel trailers, but you get more bang for your buck with travel trailers.
More importantly, is either you already have a large truck, want one, or can afford one as a 3rd vehicle, and/or you can use it for your daily driver. OH, and you have room for it...be it 3rd vehicle or not.
For me, I don't have parking for a 145+ long wheelbase truck, I have a long commute to work, my wife wont drive a pick up, and we cannot feasibly have 3 vehicles. One of which is only use 3-6 months top per year!
So, a pick up truck and 5th wheel trailer is out of the question for us right now, for the above reasons.
NOw in coming years...if we travel more miles per year and all year round, then a pick up and 5th wheel is now sensible. Or a motorhome.