I had a pair of Chota's for two years, can't remember the model. They were all right...
I just replaced them a with a pair of G4's. As far as the felt vs vibram sole, I have not noticed a difference in the river. Walking to and from is a lot nicer in the Simms. I have really wide feet and the fit on the Simms is very comfortable. I like the laces as opposed to the elastic laces on the Chota's (I know I could have switched them). I like to have my boots very tight for the support. The nice wide sole of the Simms is also a big benefit.