can anyone tell me the difference between these?  They look very similar.
www.kimbermfg.com/item.asp?ItemID=ML91550&PRICE=399&CategoryNum=21

The light gathering fiber optics are in the front of Reflex, but it's on the top of the Meprolight, a strip of it.  I hear later models place it elsewhere.

I have used both and went with the Mepor 21.  The dot is a 5.5 MOA and the dot is very clear and bright during the day.  There is some washout when there is a bright light behind you.  At night the tritium light is not as bright as the Trijicon and the Trijicon is not that bright.  What I have found was if there is a small light source at night the Mepor produces a better dot.  The Mepor is made very well from cast aluminum.

Here read this every thing you will need to know is at this site:

[url]http://www.isayeret.com/optics/m21/mepro21.htm[/url]