What are your comments, for and against the selfsteer. To me it looks brilliant. purhapse I'm to blind to see

Since you asked...,

*IF*
(1) It's free
(2) You are willing to make permanent modifications to your boat
and
(3) You are willing to be a guinea pig for a new product
then sure, why not?
We've discussed the "brilliance" earlier in the thread. It's slick, but it's (a) not new and (b) not HIS idea.
Finally, make sure you are going into it with open eyes, such as the downwind caveats (headsail ONLY) about what you can expect and that, of course, it's not useful motoring (if that's important to you).
If it were me, I'd be very clear with him up front that after I used it a year or so, I plan to 'review' it on the Internet forums (like here) and will pull no punches....I'd sing the praises of what it does well but not cover up any shortcomings I find.
If he has already done extensive testing and has faith in his product, he should have no problem with that. Bottom line, it's not a mature product with a known customer base. I personally don't like being the 'test bench' for new products, especially on my boat. I'm NOT a 'first adopter.'