The Mk6 is going around $1800 down here. Frankly unless you need a lot of the options it has the VX6 is a good deal.
The Mk8 1.1-8x CQBSS H27D is around $3500 these days. Its not a 5.56mm gun scope but is at home on a 16" 7.62mm gun.
Unless you have a life and death requirement for the glass quality, the night vision copacetic coatings etc, you don't need these optics --- That said everyone wants top dollar performance don't they?
Back to the EO, everyone wants EO speed in Aimpoint ruggedness and battery life. The EO is the primary CCO for most Special Mission Units, and down here is the SOPMOD ECOS. For a CQB-HR specific optic, it is as of yet impossible to beat. If your budget allows for replacement of the sights at a fairly routine rate (for certain models) then its awesome. I have a several years (2004) old 552 Rev E that went to Afghan - came back, went to Iraq and then I shelved it.
If I had a HR Specific doorkicking role - then I would consider the EO. For most other applications on a short (<14.5") gun, I think the T1 Aimpoint (or H1/M1 whatever) is the best bang for the buck - the 2MOA dot on the new one is usable for shooting passive thru NODS (but still oddly not as easy as a Leupold Mk6 or Mk8) the batteries last forever, and you can leave it always on - and only play with it for lighting changes (EO has 8hr auto off - but honestly you need to play with the dot brightness if you out and about so its a non issues unless its sitting in a cruiser or beside the bed etc...). However 4 year-ish battery life versus 250hrs. If your buying the batteries the Aimpoint is a clear winner - as you can buy another Aimpoint with the money you saved before your AP battery dies over the cost of batteries for the EO.
Now jump back to 1993, everyone I trust has seen BlackHawk down -- well add about 300% to the crowds in the movie, and you see why many folks decided that the 1-X magnified sights where a requirement. Leupold designed their abysmal CQ/T and as a result others went to go talk to Hans Bender at S&B. The 1-4x SHOTDOT was born, it was truly the first combat variable sight -- it was not as quick as the current issued Aimpoint (5000 series IIRC) but gave the shooters the ability to discriminate targets in crowds and distances. Advances in guns and optics lead to the current 1-8x crowd in which Leupold walked away with the title for the 16" 7.62mm gun could take advantage of the extra magnification.
At the end of the day you need to sit down and decide what your priority is, the whole mission drives the gear thing. If your a LEO, Mil, SOF, Competitive Shooter, Mall Ninja you need to decide what your 'need' is based on that, and what budget you have.
I've owned 3 Short Dots that all got sold the minute I saw Leupy's 1-8x Mk8, as frankly I no longer have a mission need (other than Zombie prep). For me the CQBSS is right at home on my 16" SR, I don't shoot much of anything else, however I do get to play with some stuff for work, and in that respect I needed a midrange 5.56mm scope that works with NV etc - so the Mk6 fit that bill.
My T-1 rides on a 11.5" gun, as its a gun I shoot at 200m and in, other than the occasional match where I prove it can go to 300yds with the T-1, for some who can't get the fact you can actually account for trajectory and if you can see the tgt you can usually hit it, it may not be as precise - and if there was a crowd that shot would not be very viable -- but I shoot for fun, at a game.