I've only ridden Millennium Flyers, still working on that visit to Holiday World for Voyage. They are the most comfortable set of seats and restraints. And as far as looks go, their old school appeal is very pleasing.
Millennium Flyers are the best train I have ridden, so the Timberliners have some stiff competition.
Either way, it is with joy that I see the roller coaster industry FINALLY moving away from the evil that is Philadelphia Toboggan Company trains.