O.K., here's the result of my research, for the couple o' people watching this thread.
Reviews of the SPARC range from quite impressive: http://www.ar15.com/forums/topic.htm...f=277&t=187104
To less so: http://www.mdshooters.com/showthread...ighlight=sparc
Various things I've read kind of sum up as:
- Used as a 1x optic, the SPARC seems to be a decent value.
- Don't count on the 2x doubler to be useful
- Vortex Strikefire may be a better value, if you don't mind the larger size
- Vortex customer support is solid- Lots of positive stories here.
- Definitely o.k. as a back-up optic or for a secondary weapon, but may or may not fit the bill for a primary weapon depending how demanding you are.
One of the big questions I had was the eye relief when used with the screw-in 2x doubler. A lot of reviews say eye relief goes down to a few inches with it, but a few reviews say its o.k. without quantifying it... So I went to the source, and tried calling Vortex...
And I have to say, I'm impressed that when I said I had a technical question, I had an engineer on the phone within about 5 minutes. Very straight-forward, no-nonsense, no b.s. Definitely impressed by their communication level and lifetime guarantee- I'd feel pretty good about buying a vortex optic that met my requirements.
That having been said- He compared the 2x doubler to the prize in a cracker jack box... "It may not be useful to you depending what you like, but it's still sort of nice to get..." I said that the reviews seemed to range from, "'The doubler is really handy, and I like it a lot,' to 'This thing is useless, and was added in just to help marketing sell more of these things...'" The engineer pauses and says, "Well, I'd have to say that depending on your perspective, both of those are correct..." I love this guy.
Ultimately, he wouldn't give an exact number of inches for eye relief with the doubler, but said it cuts down a lot on the field of view, and the eye relief won't be good enough for a scout installation. (Some reviews put the FOV reduction at 25%-35% if you're looking for a number.)
So given all that, I'm going to go with a low-mid variable scope in the scout mount I'm doing. (Nikon Monarch EER 2.5-8x) But, if you're looking at a rear-mount and want a red dot, you might give the SPARC a try if you're on a budget. At worst you get a decent enough optic to use on a shotty or something. The price is good enough that you can get a SPARC and vortex magnifier on a flip-to-side mount, and still have money left over compared to the $500+ cost of an aimpoint alone. You won't get aimpoint quality glass and dot sharpness, but if you are getting 75% of the quality for 35% of the cost, that may be a good trade for you.
Finally, if you're looking at the doubler as a selling point, two other options to consider in this price range:
Millett DMS-1: A decent 1-4x illuminated scope with a donut-dot reticle. 3"-4" eye relief, I got one of these and am replacing a cheap red dot on a M4gery. It's not premium glass, but it's actually pretty decent for the price ($200 from SWFA.com) Nice bright reticle, catches the eye without being intrusive or distracting. Reticle shows up clearly even with the battery off, which is good since the battery life isn't anything to write home about.
Burris AR-332: Fixed 3x AR-15 optic with CQB reticle. Checked out one of these briefly at Cabela's, and I liked it. It's $300, and I'd consider getting one for an AR. The reticle is not so busy as to be distracting (which was one of my concerns seeing pictures of the reticle.) Nice clear glass- Again, not like Premium German glass clear, but very respectable. Just about on par with my Leupold VX-II's, I'd say. By comparison, the EOtech 65 mil donut-dot reticle is, to me, annoyingly intrusive. It draws the eye too much, and makes you focus on the reticle, vs. a pure premium red dot (Aimpoint 2 MOA dot) which gives a nice level of "high visibility" while not drawing your eye explicity to the dot. The Aimpoint dot is just "there where you want it" without getting "in your way."
I'd also add, after checking out a fair number of cheaper red dots, I have to admit that there is some extra noticable quality in the Aimpoint RDS... Is it worth paying double or triple the price? That depends on your circumstances. But, they are definately a step above the other RDS's I was able to lay eyeballs on. Sharpness of the dot, and clarity and color of the glass were clear differentiators in Aimpoint's favor. And, based on reviews and appearance, durability is likely to be another differentiator.
So there you have it- My non-professional, non-hard-core, non-operator's view of entry-level AR optics. I am a dork, and did a bunch of research & looked at a bunch of optics & scopes over the last few weeks, primarily in the $100-$300 price range, so if you have specific questions about anything I didn't mention, feel free to ask or PM.