I like to use panasonic 80 cfm if they want a cheapo. I would personally have a hard time installing a fan in someones home and than telling them they need a Hvac contractor to vent it.
I may depend on where the vent is, if it's in the roof and you have insurance that covers roof openings they by all means do it. Just remember i am the crazy negative guy that thinks water damage can be a serious thing.