A lot of these cheaper lights lack a certain spectrum, so people will add some LED bars that only have one or two diodes in them. I have the Amazon SmatFarm light, which is pretty good for QT or temp tanks. It's a 90w fixture, so it isn't too bad and has a nice subtle shimmer. I think one of the best LED fixtures out there for the money is the Reefi Uno Pro 2.0. It's the size of an XR15, but has more power and coverage than an XR30, plus the spectrum is better and comes with 2 different lenses (stock 90 and 120).
Also, if you're growing acropora with LEDs, then you better double the fixtures or you're going to be disappointed down the road.