I have yet to look through, or test an Elcan Spector 1 x 4, however a good friend of mine has one and he really, really likes it. I hope to try it out in the near future.
I have 2 AR's a 10.5" and a 16", until recently I had an ACOG TA31F on my 16" and an ACOG TA33 on my 10.5".
As my eyes are getting older and 4X is a push at 100-200 yards, I recently purchased a NF 2.5 - 10 X 24 for the 16".
Since the TA33 was in better condition than my TA31F (it did a tour in Afganistan...........not by me!), I sold the TA33.
The TA31F is now on my 10.5".
As mentioned above, the eye relief on the 4X ACOG is not that good, the TA33 provided much better eye relief. Also with the 3x, at closer ranges I could shoot both eyes open, I can't do that with the TA31F.
I have now decided to keep the TA31F, but I want to add a 1 x 4 to my AR optic selection, more for the 10.5".
I have been considering a NF 1 x 4, a S&B short dot (if I can put the funds together), however, if I like the Spector 1 x 4 after shooting it, I think it may go to the top of the list. Being able to switch from 1X to 4X would be nice, I've read that the glass Elcan uses is very good quality. I'm not sure if this is true, but I recall reading somewhere that they use Leica glass!
I see there is a 1 x 4 Spector for sale in the EE, if I had some spare $$$$, I would definiately be checking it out!!