I disagree, the A10 is about equal per clock to a Q6600 (maybe slightly slower) so you're looking at 25% tops difference between the two, overclocked vs overclocked. Considering you won't be using the iGPU, I'd say it's a side-grade.
That's probably about correct if you assume that his Q6600 is overclocked to 3.6 GHz which I find unlikely. If you assume stock the 5800K slaps it silly.
Also he would be getting the 6800K which can do 5 GHz on air - http://forums.anandtech.com/showpost.php?p=35098638&postcount=73
So now if you assume he has the max Q6600 OC of 3.6 GHz and he'll be OC'ing his 6800K to 5 GHz we're back to 40+% faster and probably around 50% less power. That's no sidegrade.
The A10-6700 looks like it'll be a very nice chip.
If you're going to be gaming a bit (or a lot) then the i5 is worth it - I got my i5 because I needed the performance in gaming, no other reason. Otherwise the A10-6700 might be what you're looking at, or the FX 6300.