I think that they are OK, but not great. You should be able to get most acropora to live and grow, but the color is always muted in daylight situations (unless you black light). They also shadow pretty badly if the hobbyist is good enough to grow colonies from frags. The best Radion lit tanks that I have seen share the same use pattern... way up high with all channels at 100%... and not many people use them this way.
I have never heard of anybody who added T5s to their Radions that regretted it and nearly all with that they would have done it sooner. Color in the acros gets better, growth takes off a bit more and shadowing is significantly less.
Purely anecdotal here, but you do not really see many efflos, solis, millepora thriving under Radions. There are some, but not in the same proportions as tanks lit with other lights. This could be way off, but with the 200, or so, SPS tanks that I have seen with Radions, this is true. Every time that I post this, I get a few people who want to show me photos of their millepora, or whatever - I get it... I did not say that there were none, only fewer and often the same kinds (ASD Rainbow is the most common). If somebody does feel the need to PM me or post, please show me a nice 8+ inch colony sized one and not a nub or "mini colony" with three branches... I love seeing large colonies of Efflo, Soli and Millepora.
For me, this does not add up to a "great" light for these types of corals alone. I can go with a decent/OK source if you really like the other things that the offer like couch apps, small aesthetic, black light, etc.
I understand that we do not know a lot. For sure. I have seen hundreds and hundreds of tanks both locally and nationally, including all of the high end stores on both coasts that people drool about. I have gotten behind the scene tours at about a dozen aquariums and spoken with their reef keepers. I have formed my opinion on working cases over real reef tanks. This is the best that I can do - spend my time observing, talking and then make judgements for my tanks. I look hard because if they were good enough, or better, I would want to use them.