I'm no Kessil expert, but I was spurred into trying one by my situation. Haven't yet fully grown with my first go at it, but I am truly imressed so far. I had my doubts, but the way it looks, I'd rather have 2 Kessils rather than $500 spent on another LED platform. The warranty seems solid, the company is professional and responsive, and the technology just plain soars above the competition.
My first consideration was the smaller Lumigrow, for about $565. That and Procyon, Lightblaze, ProGrow and a few others were on my list, and they probably perform well and deserve consideration. Given my experience so far, if I need to expand, it will be with additional Kessils and light movers. In addition to the technology, I like the idea of not having too much tied up in one light in case it goes down for some reason.
This isn't to disparage other lights, it's just my opinion, and I'm pretty jazzed by all the advancements in LED by everyone. The one thing that disturbs me is the bad legacy of early generation LED tech. It's no wonder so many refuse to believe in the abilities of LED technology today. Plus, there is still plenty to watch out for...so be careful before you spend too much unnecessarily, or unwisely.