My Aegis Elite Custom was ordered with the 6 MOA Vortex Venom. Now after four years, it's still my only red dot, really like it for my range gun, but being my only one, my opinion is purely subjective.
Would I buy another? Yes.
Do I like it enough to leave it on the pistol? Yes.
With no experience with any of the other brands, my opinion is very limited, being this was my first RDS, but in the time I've owned it and shot the pistol, my take-away is all positive. This is the optic aboard this 9mm that allowed me to hit a torso-sized rock at a lasered 232 yards shooting BB 115gr ammo, and my W231 handloads with Berry's 124gr FMJ's with hits almost every time once the sight picture was verified in regard to holdover on the rock. Target acquisition is faster than with irons, the dot can be anywhere in the window, and if it's on the target, a hit is about guaranteed every time.

There may be better, more advanced units available as ninja mentioned, but this RDS has worked flawlessly for me so far. No complaints, no issues whatsoever; I like it.
Would I buy another? Yes.
Do I like it enough to leave it on the pistol? Yes.
With no experience with any of the other brands, my opinion is very limited, being this was my first RDS, but in the time I've owned it and shot the pistol, my take-away is all positive. This is the optic aboard this 9mm that allowed me to hit a torso-sized rock at a lasered 232 yards shooting BB 115gr ammo, and my W231 handloads with Berry's 124gr FMJ's with hits almost every time once the sight picture was verified in regard to holdover on the rock. Target acquisition is faster than with irons, the dot can be anywhere in the window, and if it's on the target, a hit is about guaranteed every time.

There may be better, more advanced units available as ninja mentioned, but this RDS has worked flawlessly for me so far. No complaints, no issues whatsoever; I like it.