I had the same dilemma, I fell in love with the look of the reefer, I had a rsm 250 and I hate the giant black top it's just distracting, also depending on where you live but here in NJ you need to add a chiller to the s line, all of the pumps they use are cheap and heat producing machines... I modded mine and even thought I am building out the 525xl I am spending more the. I would on the S 500 my only peeve is the tank size I think 525 is only 108 gal display tank but the 500 is 130 and 650 I think is 180 total volume. A bigger reefer would be nicer, that being said it is very difficult to clean the S 500 etc they are very deep tanks, I am 6-3 and I couldn't reach the bottom without my face almost hitting the water. The S series are thick and tall and the reefer is long and more shallow, so depends on what look you want.
If you like they way it looks and can get the new LED version maybe it will work for you, I have to say though planning and getting exactly what you want is better in the long run, I want oversize on all equipment and it's all DC, I have a client with this type of set up and I can tell you it's dead silent.
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