I use inline fans with scrubbers and usually go overkill with the cfm, that way it's easier to expand either area or wattage. I think it would depend the cfm ratings on each fan. If they are comparable I'd then look at the warranty and cost. You can use duct tape on the seams to stop light from escaping or getting in. Like I said, I always look at the cfm and go with 50percent or more than what I expect to need. I do the same thing with amperage rating on wiring and timer boxes. I always decided to expand when I first started and saved a lot of money that way. I don't know your exact situation though. Good luck and have fun and hit great numbers.