General opinion is that a 5er tows more stable than an equal length TT. But you know what opinions are worth. Many say a TT set up properly tows just as well.
The truck and 5er total length will be a LOT shorter than the truck and 39’ TT.
The 5er will be easier to get into tight sites since you can back in a tighter turn.
TT doesn’t have inside steps you have to go up and down. A plus.
Most 5ers have a lot of storage space under the front elevated area.
Pros and cons for each.
But you do need to check your truck payload rating compared to hitch weight.