Prevailing opinion here seems to be the Aimpoint - how about the OKO or C-More, which don't have tubes?

How would you mount on a M4 - on Handle or flat top?  Can anyone share pictures of either?

It's a matter of opinion i guess.I've got a c-more railway and ive used aimpoints.I can tell ya that the cmore Does have paralax and the aimpoint doesnt.I like the idea of the holo better than the tube.Igot the c-more caus it was cheap (read-FREE LOL)but i belive i will get an aimpiont when the funds come available. UNDERDOG

Aimpoint M2 is the best of the ones you mentioned.

If you're on a tight budget - then the OKO is a decent sight - MUCH better IMHO than the C-More.

OKO is a better implementation of the C-More.  Its easier to change batteries and its easier to sight in (simple positive clicks).  As a bonus you can also get a steel sheild for the OKO to improve its durability.  Cav-Arms seems to have all the cool mounts for the OKO if you are interested (i.e. a gooseneck for carryhandled ARs, and a steel sheilded quick-release flattop mount).

I really like the OKO. They work well and are cost effective. I have them on a coupleof rifles.

[img]http://www.supercharger.net/private/lwar.jpg[/img]

I had a C-More "tactical", man what a pain in the ass to sight the SOB in.  It does look good on an A3 receiver but that's about it, if I was gonna pose for gun magazines it'd be a good choice, otherwise don't blow a vein trying to get the thing zeroed [:)]  The C-More is expensive too, for the money I wish I bought an Aimpoint but I was lured by its good looks.

Try an EOTech.  It is parallax-free like the Aimpoint, but doesn't have that "looking through a tube" feel.  It also is easy to zero.

I have the ATN optical sight on my M4. Similar to the OKO.