I don't know about the sparc, but an eotech has a 1moa dot. I have a 2 moa on a pistol and it seems too big for shooting at 200-300 yards with. That said, I like tight groups.
Be honest what your goals are for your AR. I know people on here often don't like to say home defense, but if that's part of the reason why you bought it, in addition to the valid legal reason of target shooting, you're better off with a dot imo. I've gone through a lot of the same questions for myself recently, and I remain convinced that the eotech or rds is still the king of CQB or CQB-type shooting (Competition or the real thing). RDS has advantage that you can leave it on. Eotech, because it uses a laser, which takes a lot more energy than an LED, has to be turned on, but has an awesome reticle.
If you really don't care about that stuff and you want to shoot good groups at a variety of ranges, you can go with a LPVO and it will be better overall. For all the good things that are said about the eye relief of the Vortex Razor HD gen II 1-6x, for instance (the only better LPVOs are the Nightforce ATACR 1-8 and Leupold Mark 6 1-6), it's still not going to be as fast to line up as an eotech for close range stuff. But if you're into 3 gun and have to shoot at a bunch of different ranges, it's probably optimal and is the route competitors are going.
Since I'm going to have multiple AR-15s, I'm going to have one optimized for close quarters competition etc, and another for 3 gun. They'll also have appropriate barrels, triggers and muzzle devices for their intended purpose. Or you could just do two uppers at some point once you have the cash.