Another factor to consider is the overal cost of the setup not just the cost of the housing alone. Alot of people go for Ikelite as their housings are cheaper than an Aluminium housing for the same model camera. But when you add the total package quiet often or not the Aluminium setup is only a few hundred dollars more than the Ikelite.
Example:
Ikelite D7000 housing with two Ikelite DS160 strobes, 2 spare battery packs, smart charger, digital sync cord is approximately $3800
Aquatica Ad7000 with two Inon Z240 strobes, few sets of Sanyo eneloops AA, smart charger, and optical fibre cords is approximately $4200
The benefit of an Aluminium housing is that they are more compact, robust, have better control layout and much smoother controls. They have more accessories like Viewfinders and mini domes where ikelite doesnt have which means the Aluminium housing has more room to grow with the photgrapher down the track when they get more experience. The Aluminium housing and Inon z240 strobe setup is more compact especially when travelling overseas compared to the ikelite housing/strobe setup.
A buyer of a new DSLR setup should take this into consideration and basically put an kelite package next to an Aluminium package like an Aquatica or Nauticam and compare the over feel and design and see if that small extra cost makes ecomonical sense at the end of the day.
Regards Mark