Neither will fully cover a 4 x 8 tent. A 4 x 8 has 32 ft sq of space. Ideally you should have 30 watts per ft sq. 32ft sq x 30w per sq ft = 960 watts. It would take 2 of either the MIGRO Aray 480W or 2 of the Lumatek/PhotonTek 465w lights to adequately illuminate your tent. I like the Lumatek/PhotonTek personally, but Migro makes great fixtures. I would stick to bar lights over COBS in a tent but Migro makes both types.
I should have written that I would, of course, buy those LEDs doubled. I understand that buying more powerful version i.e. 720/600 will not give better results but only increase costs, right?
More light isn't always better. Without using CO2, you would be paying for more watts than you need and would either be hanging your lights higher to compensate (there are benefits to this) or running at less than 100% (also some benefits) but I'm not sure those benefits justify spending several hundred more per fixture.
