I have the Vortex Sparc red dot and the Vortex Crossfire II scope, and they are both excellent. Not only are they quality optics, but Vortex has a lifetime "no questions asked" warranty regardless if you buy new or used. I wouldn't hesitate buying another one.
Yea I have just a cheap aimshot on my gun that is great for up close but I need something with a smaller brighter dot. My friend picked up a Vortex red dot from a sporting goods store up here for $100 so it think I just might get one.
I use the Vortex Viper 8 X 42 HD, and think they are great. During the daylight hours, it is hard to tell any difference between them and my Swarovski's, which cost 4X as much, and weigh about twice as much. So, for the same view, and about half the weight, give me my Vipers HD's.
Now, at night, doing a star test, the Swarovski's will resolve stars into a sharp point of light, while the Viper HD's will not. They resolve stars into a fuzzy point of light.
So, clearly the Swarovski's have better optics (which you would expect), but for every day use, the Viper HD's are my choice.
I have never tried the real high-end Vortex Razor HD's. The may hold their own in a star test, but I have never had the chance to try them out.
I have 4 of the strikefires, 2 bright red, 2 red/ green. I also own a couple aimpoint comp 3's and more than several eotechs from the xps to the 512. I really haven't found any issue with the vortex, they are a great optic, cheaper in $ than the milspec stuff, but not in quality. I have used them on ar's and other guns from 22lr all, the way up to 308 winchester, never an issue or loss of zero. I really like the lifetime warranty as well. Great stuff. its by far better than other lower priced crap on the market.
I've had 2 Strikefires. They work okay but for low light in the woods they aren't worth a damn. No comparison to the clarity of an Aimpoint. You can see how much light they rob just looking through them in the store. If you are just using them on the range they will work well for the money.