I've been looking to get an LED to replace my 600W HPS in a 4x4 - wish I started before Black Friday. I can't make up my mind, so I'm looking for some opinions on my choices. Spider Farmer SF-4000 is cheaper than my other choices, but the warranty isn't inspiring (90 days free, pay ship + repair after 1 yr.) Growers Choice ROI-E680 at 680W is really too much and the controller is over $300 Optic LED Slim 600H has dimming, uses LM301H and Cree XPE. It also has a 10 yr. warranty, but I don't see much as far as reviews. Scynce LED Raging Kush at 690W it's probably overkill, but I like the dimming and spectrum control, not too crazy about using phone and I'm really stretching the budget. California Lightworks SolarSystem 550 might be a little small at 400W, but I can adjust my grow space down. The controller is priced a little more reasonably ($850 for light+controller). I almost grabbed a 480W QB light for $343 on Amazon, but I'm not too crazy about buying something that would have to be shipped to China for repair. Dimming is a big plus, but I'd rather have 1% steps than 20% - 25% or turning a screwdriver to adjust. The more I think about it, the more I'm liking the ability to adjust the spectrum based on growth stage (seedling, veg,flower).