Before we bought our South Bay, we took it to Detroit Lakes MN (about 45 miles straight East of Fargo) and the person who gave us the demo pulled the pontoon on a scissor lift trailer. Watching it go down the road and trying to load it in a crosswind was the deciding factors in us getting a bunk style.
1. The wheel spacing is very narrow, I never measured them, but they can't be more than 4ft apart, it looked like the pontoon was constantly swaying.
2. The Pontoon tubes are left unprotected, should you do something like take a corner too short and hit a curb, pole, or fire hydrant..
3. The pontoon tubes are unsupported, visit the pontoon lift thread, everybody says to lift pontoon tubes from the bottom, not stress the bolts from the top when the tubes are 'hanging'.
4. Granted the day we test drove there were white caps on the water, it took 3 times before we got the pontoon on the trailer straight enough that a tube didn't rub on the tire. The next day the salesman had to go back out and launch/reload the pontoon to get it straight. It was so bad that you couldn't even let the pontoon down because the tire would rub/hit the pontoon tube on one side preventing us from being able to lower it. I am sure you can add guides to help with this situation, but the trailer he had didnt' have them.
Pro was that it rode much lower (less wind drag), and when we launched he backed in far enough that we didn't have to do any cranking, it floated off. If you have a lot of pontoons, you can easily move one or the other. For a 1 or 2 time per year move, I think they would work great, but other than that... I will stick with my bunk trailer, but I definately see the advantages to the scissor.
Looking at the pictures I took, it appears that I really need to rebalance my current bunk trailer, I knew there was a bunch of tongue weight on it, but never realized how much difference there was between the test drive scissor and my bunk for axle placement.. see how the center of the axle is right below that one fencing brace on the scissor and how far behind it the bunk style is?
Test Drive on a Scissor Style

- ScissorTrailer.jpg (267.59 KiB) Viewed 5222 times
Bunk Style

- IMG-20120703-01653.jpg (112.04 KiB) Viewed 5217 times
Its harvesting season around here, I should really make a run to one of the local grain elevators and do some trailer weights/balancing.
-ron