We have had a Hewitt floating dock
for five years and are very pleased with it. Ours is setup to sit lower in the water than the ones pictured on their website. It's an 8' X 30' dock with a 16' ramp. The truss on ours gets wet with any kind of wave action or people on it and acts like a heat sink. With all aluminum construction and an aluminum deck it is never
hot on the feet. The dock is bright underneath it and our kids play around it without any of the fear they have had with wooden docks.
The benefits at our lake of a floating dock that moves out as the shoreline moves are huge. There are also no posts anywhere.
The disadvantage is that it is harder to set up a lift on a floating dock. It can move around more during a storm. (The Hewitt runs a cable through sliders under the dock so how tight the cable is and the direction of the waves affect the movement)
Our lake can change 12' in a year but during the summer it may only drip about 6'. The dock can move out about 25' in that time.
Ours looks similar to the one in picture 4 on the linked page.