Low wings
first off, neither high wing or low wing is actually better. Both have been proven to work. I am Jonathan Baker, the one Tom02 was referring to. I beat every composite plane, and beat very good pilots (Vern Smith, Marcus Blanchard, Darrol Cady x 2, etc.).
The GI8U2 that my father and i designed is obviously unique. Here were our thoughts...
1. a conventional tail is easier to get straight in the airplane, whereas most v-tails are super hard to get straight. My friend owns a BOP, which as many of you know has a very simple method of installing the tail straight. When it was done, it had a lot of positive in the tail, so even the latest technology isn't foolproof
2. a conventional tail provides a "truer" input. By this, i mean that when you pull up on a conventional tail, 100% of the surface travel goes into pushing the tail down, and therefore making it turn. On a V-tail, (Deflection) x cos(35º) goes into making the plane go up. This means that there is a counteractive yaw input. This means that more deflection is needed to have the plane turn, which is drag.
3. low wings benefit from ground lift on takeoff and landing which means shorter takeoffs and easier landings
i will talk later some more...