Hard to answer. As a RDS, it's just OK, IMO, but it's also very inexpensive. At the $50 price you can find on Amazon, my only real question is "does it work and will it break easily?" My impression based on online reviews and the one that I've been using since last December is that it holds zero and holds up to recoil, but it's not super-clear when looking through and it doesn't have some other features that other RDS have like auto-on-off and very high battery life, to name a couple. Is it the "best budget value?" I think the answer will vary from person to person based on how low they're willing to go when buying stuff like this, or what they consider the absolute performance floor. If you're looking at RDS well below $100, I think it's pretty good. If you can spend a little more than $100, you can get a RDS that's arguably quite a bit better.
FYI, I had to change the battery on mine for the first time today, after about 9 months of use, but that's because I apparently left it on (on the brightest setting, no less) the last time I had it out - oops! Editing for clarity: I typically have it off unless I'm at the range.