I'm in the middle of switching to radions now, currently have one over the 50G cube I'm trying to sell. These are some serious serious lights. I don't see myself using anything else other than supplemental T5 in the future
I have run radions for a long time. Currently have 3 upgraded to Gen 3. I think the key is stability. In other words not constantly playing with the lighting schedule. I'm thinking about adding some DIY diffusers because I can't bring myself to pay 200$ for scratched plastic. I do however think that would be a big upgrade on these lamps. My biggest complaint would be disco ball effect which would be corrected with some diffusion. It would also add some spectrum distribution and hopefully help with shadowing and spread. Even if I have to give up 25% par most are running them well below 100 and have room to amp it up.
I went from gen 1 > gen 3 > T5 > reef breeders > gen 4 pro. I love my gen 4 radions. I tried the t5 again, but the heat produced were killer for me. Then the reef breeders didn't seem as nice in color for my eyes. Just my personal opinion on those. Like said before, stability is key with these light and the temptation to adjust the schedule is what makes for bad results.