Eotech is always confusing because they have about a MILLION different models... Forget about all the various part numbers and such... Here's what it really comes down to...
A) What type of battery do you want?
- The model in my pic above takes standard AA batteries. The advantage to that was at the time the other option was the N type batteries... Much harder to get, more expensive, and not a whole lot smaller. Now you can get one that uses a single 123. The 123 can be picked up at your local wal-mart so availability isn't a problem. It makes the eotech much shorter so it takes less rail space. Not a problem if you've got a big arse monolithic like the XCR, but maybe a concern if you don't have much to work with. It's also lighter.
* So while I'm perfectly happy with my AA powered EOTech, if I was buying it today I'd get the 123 powered model.
B) What type of reticle do you want?
- There's a ton of options here too, but in general it works like this... Do you want a 65moa circle with a 1moa dot in the center (as mine described above) or do you want a single 1moa dot. There are other models with ballistic drops calibrated for .308, .50, etc... less lethal, and just about everything imaginable, but the circle dot or dot are the two basic options.
* I can't see any reason for going with the dot over the circle dot. Just doesn't make sense to me NOT to have it.
C) Will you be using it with NV equipment?
- You either will or won't. If it has the option to go into NV mode it costs more. If you won't be using it, then you can leave it off and it'll cost less...
* I don't have NV gear, so I'd leave it off...
D) Any other non-standard things you're looking for?
- You can get them in various camo, you can get them with buttons on the side (to make use with magnifiers easier.. I.e. the magnifier doesn't get in the way of the buttons. You rarely ever change the buttons... You turn it on, adjust it's brightness for the current lighting and then you don't touch it again... Not a necessary option...
* I'm a "standard" kind of guy...
So anyway, what do we learn from all this? If I was personally buying an EOTech today, I'd get the XPS2-2. Circle dot with 123 and no NV support.
You might want something different, but don't get confused by the models, just focus on what features you do or don't want, and then you can pinpoint the model from there.