My son purchased mine on Amazon. Was a cool Birthday present.
I'm also using a opaque piece of plastic as a diffuser. Eliminating most of that disco effect that you can get with led fixtures.
I have two visparspectras over my 75 gallon 48" tank, I've had the whites at like 2% and the blues were at 30% but I've had to crank it down since the corals with ticked off over something.
I like them, but on one of them the timer is off, they both started out with the same time but now they're 9 minutes apart which is annoying visually for those 9 minutes when the lights are transitioning but I could always go and change it if I cared that much and let them slowly grow apart again.
I had them for a year this March and August and when I did a super clean on my tank this week I took them off and opened them up to clean out the dust. They'd collected quite a bit but it was fairly easy to do. Did void the warrantee though.
I ran 165 watt SB Reef Sbox lights over my all SPS tanks and got great color and growth. Do not have any experience with Vipar Spectra but have heard pretty good things. A lot of people are buying the Vipar Spectra and "upgrading" the PCB board to the SB Reef. From what I read the logic behind this is that the Vipar Spectra comes with a longer warranty (not sure if is just through Amazon or if it is through manufacture) and seems to be built a little better while the SB Reef is thought to have a better spectrum. Again, can't say which is better as I have not used the Vipar Spectra, but I can attest to the SB Reef lights having good spectrum and spread but not being the highest quality build. Hope this helps.
Take a look at Bloomspect as well. They are 95% same as Viparspectra units. Only difference is that they have 2 UV LEDs (VS does not) and their reds are in a bit of a different spot. If you decided to go with VS, see which one between these 2 is cheaper and get that.