I grow in a 3x3 and have used a Spider Farmer SF1000 and now a Spider Farmer SE3000. I love my SF1000, and while I only have 3 harvests under my belt I felt that it did a great job.
I had an opportunity to upgrade to the SE3000 on the cheap and decided to take the plunge. I can't comment yet on how the light performs as I'm only a couple weeks into the first grow, but so far I've got a lot to look forward to. I screwed up the seedling feeding and I believe that she might be a lil stunted for her age, but her stems are thicker than a bowl of oatmeal! This might have something to do with the genetics, but I've never had a plant in early veg get this hardy, this quickly.
The SE3000 produces more heat than the SF1000, but you're getting 3x the output and better coverage. The nice thing about the SE3000 is that you can run the driver on the outside of your tent, saving some heat.
I'm finally dialed-in when it comes to temp/humidity, so I'm excited to see where things end up.
Would the SE5000 be overkill for a 3x3?