Well, I have limited experience with RDS. But I've used the Leupold 1.25-4X VXR a good bit.
First of all, it's dot is not near as bright as those on the several RDS I've played with in daylight. However, the tactical reticle that comes with the scope is really fast. You simply put the circle on top of the target a fire. Your eye automatically centers the reticle.
I've never had the adjustments not move the rifle's zero just what they are suppose to do. No, I have cranked it to the extremes of it's adjustments and back dozens of times.
Last of all, there a significant difference in 1.25X vs. 2X. If speed is very important, I'd say 1.25X is worth having. E