gotcha, I dunno man....the AR15 and AR10 feel almost identical in my hands, there's a bit more recoil on the 10 than the 15, however, that's easily remedied with a stronger buffer spring. If you're thinking PSC/PMC, I'd honestly be thinking more punch = more better. All of my deployments resulted in me being happiest when I had a .50BMG or 7.62mm rifle in hand. If I had an M4, it was with an M203 attached. After watching people be hit with 5.56 NATO and pick up an AK and return fire afterward, I never saw someone get tagged with a 7.62mm from an M24 and try to move at all. The big advantage to 5.56mm is that the ammo load out is lighter, **BUT** in my mind, it was always worth it. (though, I suppose it depends on what your combat load out is. for the MG guys, yeah, it was a significant difference in weight. for me, it wouldn't have mattered at all) if customization is your big thing, anything that fits the AR15 typically fits an AR10 as well, so, you can customize just as heavily.
check out
http://308ar.com/ as well, maybe get some ideas there too, I mean honestly, it's like the debate of frontier vs titan. if you never need to make it work hard, fronty is fine, but if you need to pull a big load, there's no replacement for displacement. (the same applies to bullets, check out penetration tests, not even getting into the way .223/5.56mm tumbles so it's more likely to ricochet)
oh, and for **HOME** defense, if you pull out an AR, you're trying to kill neighbors, home defense = 12ga with buckshot, preferrably a pump. home defense moments are much higher stress than anything else, and the lack of required pinpoint accuracy absolutely makes the shotgun much more useful.