I'm not that familiar with the i4. I've never paddled it, but I heard from one person it wasn't too bad at all. I guess that doesn't help you at all...
If the Big EZ is still around now, it'll probably be fine. At stages WaveSport did have plastic issues but I'm sure it'll be good to go. Have a good look at any boat before you buy, also look at where the seat bolts to near the cockpit rim. Any cracks, move along swiftly
Might be a good idea to speak to a local shop for more advice.
I'd also say read through this article I wrote (the pictures of the outfitting is outdated but the info is spot on):
adrian.playak.com/index.php/articles-mai...rted-choosing-a-boat
I've tried a Flip-Stick before. It was a good river runner! The only gripe is the outfitting, and on the boat itself it has these pretty designs which look cool, but remove skin off your knuckles....
Any more questions just shoot