My own experience, having spent several thousand dollars on black rifle optics over the years, is that its hard to find a do all optic. Usually you are giving up something to gain something else. It all boils down to the purpose of your black rifle and its capabilities in terms of accuracy. Typically you are left to decide, is it a CQB rifle, a do all RECCE rifle, or a SPR/DMR rifle. Most people settle on the do all Recce approach, as it only involves having one rifle, however your are left compromising CQB, or precision at range. I find that I am most happy with my CQB rigs, and SPR rigs where the choice is easier for optics. If your rifle is not consistently accurate (0.75 MOA to 1.5 MOA v.s 1.5 MOA to 4 MOA), than putting a magnified optic on it, is not as important. However if the rifle is capable of accuracy, it can fill a variety of roles and then your optics choices are greater.
For a CQB rifle, I like the Aimpoint T1/H1, hands down. I've used other aimpoints, which are all good, but the T1/H1 is less bulky, weighs less and is just as robust. I also like the Eotechs, which I have the most experience with, but its heavier and bulkier and I don't like the battery life, or button controls. With practice and an accurate black rifle a Aimpoint T1 can be used to engage man size targets, out to 200, or 300 yds. With an accurate short barreled AR, like the free floated SS Noveske's you can push your CQB rifle into the realm of a Recce rig. Keep in mind that the red dot on an T1 is 4 MOA, so shooting for group is damn near impossible. The only objective bad thing I have ever heard about the T1 was from a 3 PPCLI soldier's experience in Afghanistan, who told me it is horrible at reflecting sunlight which in a combat zone can compromise your position.
For a Recce Rifle there are a lot of choices. I like the NF 1-4's, Trijicon TR24's, S&B Short Dot, Elcan Specter DR and NF 2.5-10x24. The S&B Short Dot best bridges the gap between CQB and Recce, however its expensive, heavy, and bulky. However it's like a NF 1-4 and Aimpoint T1 all rolled into one, the glass and reticle are awesome and the eye relief is good. You can also make precision shots with the fine reticle. The NF 1-4 is a cheaper alternative to the S&B, although it's still expensive. It is less bulky then the S&B, the glass is good and there are a variety of reticles. I find that it is not as good at CQB as there is no red dot and the illuminated feature washes out in day light. I also always end up wanting more magnification, and since the 1-4 is not excellent at CQB, you might as well just get the NF 2.5-10 which is only slightly longer. Get used to shooting close target at 2.5 and your good to go. Its no different than learning to shoot CQB with an ACOG, or fixed power Elcan, except you get the extra magnification. As for ACOG's and Elcan's, they are great optics, however the fixed power characteristics mean you are compromising on both CQB and shooting at range. They make great infantry rifle optics when all your are ever shooing at are man sized targets, usually between 50 to 400 yds. As for the Elcan Specter DR, I love everything about it except the eye relief. Same thing goes for the ACOG TA31F, or RCO, where your eye has to be so close to the scope that it makes it hard obtain your target in the reticle quickly from a slung, or ready position, or from awkward shooting positions. That's a killer for me. At the end of the day, the Trijicon TR24 is probably the best 1-4 bang for your buck. The glass is super clear, the eye relief is good, the reticle (Grn, or Red) does not wash out, and its robust. The TR24 is larger than the NF 1-4 and it's reticle does not lend well to hold over, but its a damn fine scope, none the less. If you want a variable and can afford it, buy a short dot, otherwise the TR24 is excellent. If you don't mind sacrificing eye relief than the Specter DR would be a good choice. Next would be the NF 1-4, and then the fixed power optics like the ACOG's. Personally, I'd just get the NF 2.5-10, but I'm biased towards maximizing accuracy.
For a SPR Rifle, I like the NF 2.5-10x24. However any quality precision rifle scope will do as long as you don't get too carried away with magnification. What I like about the NF is that it's a precision rifle scope packed into a relatively compact, robust body. It best spans the Recce to SPR Rifle role. There are other scopes with the same capabilities, but they are all bulkier. I can QD my NF onto my CQB and shoot MOA groups with it and slap it back on my SPR rifle and I'm good to go quickly.
At the end of the day, I run a CQB (T1) style rifle and a SPR (NF 2.5-10x24) style rifle. My CQB rifle can do what a Recce rifle can do, as long as I'm not trying to to shoot tiny groups beyond 50 yds. I can still hit pie plates out to 300 yds with practice. For shooting for group or at longer distances, my SPR rifle fills the role. I know that all the options I mentioned are pricey, but they illustrate the pro's and con's of the different styles of black rifle optics out there. You need to figure out what role your rifle will fill and then choose the type of optic for that role. Your budget will dictate weather you buy the real deal, or a knock off.
Here is a great article on fighting optics for the AR:
http://demigodllc.com/articles/fighting-carbine-optics-short-guide/