Hey! The R60 is a great tank. I had one set up for a little over a year before upgrading. The tank now lives downstairs in our office. Here is a link to my build thread at the time:
https://www.reef2reef.com/threads/ultum-nature-systems-r60-build.1083256/
The pros of the R60 are that it is compact, so if you are pressed for space, it is perfect. It's also the only cube-shaped reef system we make. Ease of maintenance on a 32G system is also great, and collecting all the necessary equipment is also far more affordable.
The main con would be the smaller electrical cabinet. I found that it was a very tight fit to put all of the power blocks of the lights, pumps, etc, into the cabinet. The larger models don't have this issue, as they have full-sized electrical cabinets.
Of course, I'm biased, so get others' opinions, but reach out if you have any questions about the tank.