Torsion are what most come with now. I know that one drawback to a torsion axel is that if you bend one or it needs to be replaced they are very expensive to replace. $1100 for my ranger trailer, and $900 for my ezloader (Lund) trailer. I think the torsion offer a smoother ride, so there may be a less likely chance equipment gets bounced out of the boat on the road. I had that issue on my first boat trailer. It bounced three tackle boxes out
Torsions ride so much better and bounce less on our super smooth roads we have. We have them on our new horse trailer and a world of difference in pulling it, most times don`t even know it is there.
A lot les moving parts to wear out and become loose.