I installed this kit in August and since then my frogspawn has grown from 2 heads to over 12. My toadstool has gone from about the size of a quarter to about the size of the bottom of a popcan. GSP has grown really fast, luckily it isn't on the main rockwork. Polyps have gone from about 10 polyps to about 40. I'm not sure how fast most of these corals grow in general, but the growth has greatly improved over just the stock hood. I had the stock hood for about 6 months and hardly noticed any significant growth.
For the price it is a good deal at least to me because I have cats, like the closed top look, have no desire to put sps in a nano and it gives me good growth with good colors.