The cheaper ones may not have the spectrum needed to keep a coral's colors (acans in particular tend to tuen red under LEDs), and when turned up too high they are quite capable of burning corals.
I hear that the Radions and one or two others (can't remember which) tend to grow corals as well as T5s.
I like this thread
More?
I tried a couple coral rescues, but my tank and I were still too new. :/
My scooter dragonet was a rescue, though. Poor thing had an extremely pinched tummy, but she's bulked up and happy now ♡
I helped out some freshwater fish in the past, too. A set of gold barbs were horribly thin, so I fattened and rehomed them.