The only thing EHS offers as an advantage is that it is WAY stronger, and will outlast the cheap strand. It is much harder to install, and is pretty difficult to even handle, since it is so springy. The cheaper stuff is easier to cut and install.
Dynamic has it's applications, but I am not a convert to full time use. I think it is best suited for supplementing strength in a tree for customer fear reduction. When it comes to saving a tree that probably should come down, install something that will carry the load all the time.
If you are charging your customer to do a good job, then use EHS and do the best you can.