I have an m4 style post ban upper on the way and I was pondering my sight choices.  I can't afford the optic setup I want right now so I was thinking of either getting a detachable handle or the ARMS flip up sight.  I like the idea of getting the arms sight and just leaving it on after I get an aimpoint on it.  I just have a few questions about the arms sight.

#1 is it accurate, does not wobble or shift around

#2 can I use the arms as a primary sighting system comfortably or is it really an emergency only sight?

#3 Is the arms durable, say that I might not get a scope for a couple of years will I be able to count on the arms to still be good and tight?

#4 does the arms have selectable peep sizes, I think I remember seeing a flip up that did but I can't remember which it was.

Thanks!

I have a couple of ARMS #40s and mine work great.  Should set you back $75-$95 each.

Mine do not shift or wobble.

You can use it as a primary, if you want.  I rarely take my optics off these days, but it is nice to know it is there.

Very durable, good warranty.

Peeps flip like the A2 sight.  One note, though, the long range aperature has the top ground down a little and a notch cut in the top.  It appears to be done for clearance purposes so that the sight is flush when folded.  I suspect that the sight can be replaced with a standard, match, or Tritium model, if you wanted.

Just my .02, YMMV.  Hope this helps!