I'm doing a bunch of research on replacing my deck and have seen both of these materials recommended. I talked with a local lumber supplier (not a big box retailer but an actual lumber yard) and the guy told me MDO was designed for outdoor signs, like parks etc.. and was water proof and perfect for boat floors. I just wanted to get a few opinions from folks that may have used one or the other or both for that matter, and see what people think about this. Thanks for the feedback.
