i haven't heard any negative reviews of marcum cameras yet. probably are out there, but they are not in my face. if they were so bad, they ought to be.
i just got one installed into my marcum lx-9 (no ice to test drive it yet. looks great above water!)and has 2 years warranty, so if QC is bad they will be busy fixing their mistakes for sure.
the actual camera is made in china. probably just like all of the aqua-vu is. marcum is made in usa otherwise. americans supporting americans.
the main difference i know of is the lighting. marcum uses bright white led's and aqua-vu uses infrared lighting. i hear mixed stories who's see's better in low light.
one can buy a infrared or bright while led light to test it with. maybe both at the same time is the ticket. used to be able to buy add-on lights for underwater cameras. i had one.
check aqua-vu's warranty to help make up your mind while waiting on more comments.