I like the styling better on the Nautilus, but I'm concerned about the "ceramic paper" (read: fiberglass, question mark?) used in their coil heads. Unless and until they switch to something more traditional (I hear through the grapevine that they might be switching to Japanese organic cotton soon, due at least in part to the backlash over the ceramic paper issue), or we have more information about the materials they're using right now, I think I'll steer clear of Aspire and their BVC heads, no matter what kind of clouds they can chuck.
Another option I've considered, besides the Aerotank Mini, is a Protank 3 (the regular one, I think it's about the same size as the mini Nautilus) and picking up the extra airflow control base version 3, with the discrete multiple air holes instead of the analog "wedge" design like in the Aerotank v2 and Mini.