I have had both with the same truck. Both have their pro's and con's. Storage inside and out on a 5th wheel is greater. Yes you do lose most of the bed space, BUT you can put way more gear in the front basement of a 5th wheel. More interior cabinets as well.
Pro's on the TT are more RV for the buck. Less money. One level floor.
Cons for the 5th are few. Interior steps, pin weight and loss of truck bed space.
Cons of a TT are less storage, somewhat harder to hitch up, requires a WD hitch and sway control, and the one that no one ever mentions is that with a TT when you're hitched up and want to get from one side of it to the other, you either have to climb over the tongue or walk all the way around. When a 5er's hitched you can walk between them. IMO it makes it easier when setting up or taking down.
with that being said it seems that lately the DW and I are starting to lean more towards a TT on our next purchase. We want more room and with our trucks limits on payload we can get a larger TT that will weigh less. Draw back is that the whole setup will be longer. With a 5er you're about 4' shorter going down the road. That 4' also comes in handy when looking for a camp spot.
As far as towing goes. 5th wheels win hands down as they're a simpler design. With a TT you need to dial the truck and TT in and if thats not right then you fight the whole setup. Yes you can still have a good tow with a TT but everything's got to be right.