No there isn't in my opinion. I've seen just about every 1-6x there is and I even own a SS 1-6. A few are close, but the MK6 with TMR looks like the total package to me personally. And Scott at Liberty Optics would take good care of ya.
While i don't think wind/elevation calls are going to be soaking up much of my time on a 16" 308 gaser I wasn't a fan of the capped turrets. They don't appear very robust, also the decent reticules cost a few bucks extra, not a big deal but just what kind of turned me away.
Yeah, the thing is most definitely daylight bright. The type of illumination requires your head to be in a fairly picky position however I didn't think it was that bad. I still think its a total package type of scope in its class.
I have not seen the USO 1-8 or the Bushnell. I have seen a CQBSS with Horus however. For the price difference, I'd rather have the MK6. A 1-8 is a little different and depending on your needs may be too much. They are certainly too much money.
"Better" will be subjective to your needs and expectations. I have a USO 1-8 and in my use and preference it out shines my MK6 in every way other than the turrets. The USO has a christmas tree reticle so I have no need for turret use under most conditions.