I operated Twin Otters on Wipline 13000s (straight floats) along side Caravan Amphibs. Its a hard question to answer because to my knowlege there are only a few in service, a couple private ones and Ontario ones with the "Fire Floats" that can scoop and dump.
The Basic float structure is very much the same on wips, and I have seen the amphib gear on the Otter only once and it appeared to be scaled up version of the Caravans
Basically castoring nose wheels that can get a good shimmy and dual mains that retract just behind the skeg of the float.
Land operations are always fun, it’s a bit like a shopping trolley with a sweet spot (speed) that you will learn to avoid. The gear is not made for serious land stol ops but will handle unpaved surfaces if no better option exists.
Avoid if at all possible over-nighting an amphib on salt water, we had to several times and it then creates havoc with the main wheel brakes and other main wheel assembly items that don’t like sleeping in water.
Other than that after every landing the whole thing needs a good bath in fresh water and if your really professional use a compressed air gun to remove and water.
Basically very versatile and reliable when well maintained, if you don’t maintain it then you will be having constant brake and system reliability issues.
PM me if you need more.