Maples are funny trees. They respond differently according to the bazillion micro climates USA has to offer. For the most part the trident maple will offer the best performance for bonsai technique, while the palmatums are hard to beat for leaf beauty. They are not as forgiving as trident while trident have very few health problems, palmatums can be wrought with problems.
Palmatums work very well as larger trees and tridents seem to be better for shohin sized trees. Tridents leaves reduce very well while palmatums reduce, just not as much. That is why they seem better for larger bonsai. Most all the maples have the same internal clock as far as bonsai technique, with tridents being more hardy as far as chopping and grafting.
Chopping tridents is almost bullet proof, while chopping palmatums can end in death fairly easily. Palmatums are more susceptable to verticillium wilt while tridents never suffer from this affliction. Many beautiful palmatum species are grafted on to mountain maple roots while tridents do well on their own. Getting good rarer palmatum stock with good grafts is more difficult to do.
I may seem biased here but after growing over 100 maples as bonsai I can speak from the heart about tridents while palmatums have not been as good for me. I have a few but they tend to be a little finickey for me.