If you're paddling mostly medium to big volume rivers (like a low Zambezi) then the Diesel might be a better bet. The flat hull will perform better in big, pushy stuff.
Otherwise the Solo is really great! I've been using mine since April 2007 and still love it. Yep I'm sponsored by you may think I'm biased, at least I'm honest. I still believe the Fluid boats to be of a great quality and their designs very sound. I know several people your age who are very happy even on class 2 and 3 with the very rare 4.
Hope that helps, although you did post 4 weeks back..