I have a 55 gallon reef and no longer use my UV because UV kills bacteria and I figure that the more natural a setup I have the better. However, for a FOWLR my UV kept my tank water clearer. I ended up using the UV only when I would see a fish in my tank not look well. However, after a bit of time and experience I no longer use a UV as my focus is reef.
I have read that a UV can be beneficial if you have fish and you may not want to use it, on a regular basis when having corals. However, I am sure you will get various opinions.
I forgot to mention that I have the turbo twist. Works very well and made my tank clear. This usually gets good reviews. Just make sure that the pump you use is the correct size for the flow. Usually, slower flow is better for UV.