That is a tough one and within days of you picking one a new improved one will come out. Like RbtAsk said look at the PAR/PPFD maps I will add ignore what they say the coverage is becasue most lie. I also suggest doing some research on PPDF and DIL to decide what will work best for you. I strongly suggest getting one with a dimmer unless that is a really tall 3X3 tent. Nothing wrong with a 400W HID with a dimmer for that size tent either