Well, trying not to give way to prejudice but I have seen the things sailing... yes they can make some ground to windward and probably do so under a wider range of conditions than the big sister; the proportions are closer to a functional sailboat. But how much fun is it? I would hate to have Opti kids sailing circles around me.
OTOH as a floating base for an afternoon of kayaking, swimming, Opti-ing, etc etc, it would be great. Especially for the money. I'd think hard about a tri-toon though, and maybe rigging a dipping lug on it to keep from being so dependent on fossil fuel.
You're asking the wrong guy whether it's fun. Remember, I sail a Sun Cat and manage to find that fun. Poor sailing performance does not equate to lack of fun for me. Sailing = fun, and that includes the time I sailed my 15 Whaler across Biscayne Bay using the Bimini top as a square rig.