RE: Idiots questions about Boats
What you're asking about is a surface and sub-surface drive system. mostly it's a personal preference, the way the boat comes and some boats are specifically made for one or the other.
A surface drive allows the engine to rev a little higher plus it will spin a bigger prop. One sometimes downside is that it is more prone to cavitation or if mounted improperly you can get chine walking (the boat rocking side-to-side).
Sorry, I don't have any opinions on either of those boats. I did just get their smaller version of one that I'm building, the Delta Force 12 and waiting for some hardware to show up in today's mail. The boat was made for electric power but I'm building as a nitro powered version. I've got a lot of work ahead of me.