As for the ikelite housing, everything is accessable as well, simple to reach and use. I guess it all depends on what your plans are for underwater photgraphy. I was going to get the WP-DC90 housing but after seeing it, I wasn't crazy about the way it looked built. No offense to anyone with it, but it just didn't look as sturdy as the ikelite.
Pros on the ikelite:
Thick Polycarbonate build
Additional lenses and filters can be attached
200' depth rated (though I doubt I will be doing that anytime in the near future
)
Metal controls
You can see that the gasket is sealed through back portion of housing
Disadvantages:
$200 more than WP-DC90
alot bigger and heavier than WP-DC90
The canon is great if you don't want to spend the extra money or don't plan on getting different lenses and want something that is easier to travel with without having to go out and get extra cases for protection since it will fit in most camera bags. Both do the job well but the ikelite will give you more options if you plan on taking it the photography a little further by allowing macro and WA lenses.
If they would have put a round port on the WP-DC90 like for the A95 housing I prob would have went with that but I had some extra money burning a hole in my pocket and decided to go with the ikelite so that if I choose to get extra lenses I won't have to get another case, though I may pick up the WP-DC90 for snorkling since the ikelite can be a bit bulky to carry around.