The black and gray theme means the RZ820 BK is relatively neutral in the color scheme department with only the CPS logo in orange jumping out a bit. Still for a neutral color scheme or black / white / gray build the cooler will be right at home. The overall build quality feels great, and the design is spotless. I mean sure, big and boxy might not be to everyone's tastes but here I do feel it works. Its simple nature means other components in a build get a chance to shine and that's okay too.
When it comes to memory clearance sticking with lower profile heatsinks or in other words standard height memory is the best option. While the fan can be raised up to compensate you may encounter case compatibility issues as a result. Still for those using standard memory you likely won't have any real issues, so memory compatibility is pretty decent while not perfect. On the graphics card side things are a bit close for comfort. While the cooler will clear the GPU it is a tight fit and issues with clearance will be more common on MATX or Mini-ITX.
When it comes to the ARGB lighting it is very, very limited in scope and while it doesn't look bad it feels more like CPS PCCooler wanted to tick a box on a checklist for the RZ820. Especially when you consider the logo is also illuminated but rather than being ARGB it's a white LED behind an orange piece of plastic. These two combined just don't look all that great. Lighting should be uniform or fully configurable, mixing customizable with a set unchangeable color doesn't make sense.