don't know about the muller-- haven't heard much about it.
also no experence with the bushnell 1-4x i suspect that both units would be OK for an ar-15.
SWFA sells a excellent scope in 1-4x24 with illumination called "optisan mamba" and it (at least the one i got) has excellent daytime visible red and green illumination. it also has very good glass considering its price.
i have had one of these for few months --and i'm really liking it.
it does have just a couple little things the "eye box" is a little tighter than my PA-1-4x24 at 4x,
the daylight red/green illumination is too bright for full night time darkness --like night time hog/varm hunts.
it is a very bright scope , the turrets seem a little soft, you can't feel the clicks but you can hear them --their very fine like a watch.
so far it has held zero perfectly well.
it does pretty well when you use it like a red dot and fire with both eyes open @ 1x too.
it ain't "perfect" but i haven't seen a perfect scope yet --and these compare well to some very expensive 1-4x big game type of scopes.
and the best part is SWFA has these brand new with an excellent 30mm cantilever mount for $149.99
you can't beat that deal with a stick-- if your in the market for a illuminated 1-4x scope with good glass.
as far as the eye box being tight --it is only tight @ 4x from 1x-to 3.5x it seems very open and forgiving.
i figure optisan wanted the sweet spot on this scope in the lower mag ranges to help when you use it as a red-dot @1x
and it is only a little tight @4x--