I will say this:

You may not be ready for any seaplane. Flying off the water is very different that flying from land.

That said, I highly recommend the Neptune. I have had several Seamasters and it is the best all-around seaplane on the market. When my current Seamaster meets it's demise, I will probably replace it with a Neptune (Only because I have heard that they are better built)

And I will beg to differ from anyone who says that a trainer on floats (Or ANYTHING on floats for that matter) is a better way to go.

No way! The floating hull design of the Seamaster/Neptune is MUCH more user friendly on both take off and landing.