Discarding price, image quality and the camera/lenses weight differences, the housings are not that much different in weight. The PTE06 is 5lbs without arms. The PTBK-E02 arms bracket is about 1kg... which brings it right back up to 7lbs again. Arms and strobes are the same for any setup (except one has to look for optical strobes only vs sync cord capable housings).
Looking at the dimensions of the housing : PT-E05= 212.5 x 170.5 x 147 mm vs the aquatica 5D2 230m x 195mm x 145mm. Again not much savings against a camera which is bigger and heavier. An aquatica D90 housing (which is closer in performance class) is 216 x x 171.5 x 133 mm and weighs 6.25lbs/2.85kg with grip. That's aluminum vs the "lighter" poly construct.
The weight savings is only significant on the camera and lenses. A few hundred grams on the camera and whatever lenses, I'd say you'd save about 2-2.5 lbs or about 1kg if you have a many lenses and 2 bodies. I absolutely agree every bit of weight counts in these times but there isn't such a significant savings in the magnitude of 30-50% overall.
I'm not advocating either systems as people have to choose what works for their budget/needs/whims. I just want to reiterate that research is crucial in making the right choice. I spent 2 mins in Google to find that info and 7 mins to write this down. That's more than I should've really ![]()