Given the two options you outlined, I'd go with the 250 watt over the 150s. I agree that the 250 will penetrate better and is big enough for 4 plants. But those wouldn't be my first two choices. I'm an LED grower, so of course, that's my preference. If not an LED, I would put a Quantum Bad Boy in there. I'm in the process of helping a friend set up a closet grow. We looked at several options, including LED, out of his price range, (well, not really, but he's a cheap bastard) two 250 watt CFLs or a Bad Boy. We're going with the Bad Boy. His closet is only 22" wide, so we can't fit an 8 bulb unit, so are going with a 6. Less heat to deal with and they do a great job.