I find it hard to believe that no one has reviewed this reverb yet. I worked with Hans as a beta tester on this a year or so ago. I was always hoping that he would combine his room machine 844 plugin with his reverb. Well, that's pretty much what he has done. R2 has a very easy to navigate and edit gui interface. Han's has included two different reverb algorithms in R2. There is seperate early damping for both ER and reverb as well as a late damping configuration. The mixing possibilities are nearly endless. R2 is very flexible. But, "how does it sound?" you ask. Well, that all depends. Hans has included some presets with it that work as starting points, but to get the most out of it, you really need to do some tweaking. There is so much that can be controlled that is can discourage people who just want a few great presets. For me, this is my "go to" reverb. Not because it's the very best sounding all the time, but because it can do a good job at so many things without sucking the life out of my CPU. I have made some presets that I think are very good and I tend to use those.
In way of comparison, R2 is a bit like M2 but with an easier interface and less power hungry. As far as algorithmic reverbs go, R2 is pretty close to M2, but I tend to use it more becuase of the above reasons. I think the combination of good sound and low CPU usage is what makes R2 a great deal.
So, what's not to like? Well, some settings can sound a bit pinched or tight; not airy or open. (how's that for vague?) Also, at very long decays with a very large room size, you can hear some patterns in the tail. Note, that this only occurs at extreme settings, that I don't use anyway. And lastly, I sometimes wish the reverb were just a touch wider in the stereo spectrum. But these are all small points.
If you're looking for another reverb with a lot of flexibility, give R2 a try.