I love them, almost bought the pac 1200 (two of them) with Andre from Oregon. I couldn't get the cash together ($%&#@!)
They are river rafts first and foremost, half the cost of a driftboat and can be disassembled to store in a closet or the back of a pickup truck.
I own the Buck's Bag Bronco and I love it. It has taken me down numerous raging pacific northwest rivers up to class III.
I use it occasionally in salt. The frame is aluminum, but the new ones are stainless. Given a quick rinse with a garden hose I have not suffered any problems.
It does have greater wind resistance on ponds but you can paddle at great speeds unlike the float tubers who are submerged up to their waists and must move very slowly. I recently was boogie-ing past a float tuber who said "man I wish I had one of those". I asked why? and he said - being in the water and kicking makes you need to pee, and then you are in the water and need to kick like crazy to get to shore. He did not get blown around by the wind though.
Everything has it's advantages and disadvantages ;-)