I can't comment on the Fantasea. Ikelite has a big following and is competitively priced. I'm not a big fan of their style of housing and especially their ports/ zoom & focus rings. I have friends who have produced some nice photos with their Ikelite 350D housings. But I've also had a friend flood one... (I like to think that was user error...)
Most pros will tell you you don't need TTL but to be honest I find TTL pretty accurate for macro shots and very helpful for someone just getting into u/w photography. Occasionally now, as I've gotten more comfortable with the camera and how it behaves u/w, I've been switching to manual strobe control for some additional flexibility.
I've been happy with my Sea & Sea housing (350D converted to fit my 400D). I am NOT happy about what Sea & Sea did to their 400D housing by removing certain buttons on the rear and not making the TTL converter optional (it's now built into the housing).
Take a look at the Seatool 400D housing. A bit pricey but it allows you to use optical cables for TTL instead of requiring an expensive electronic TTL converter and cables. The housing is tiny as hell. Downside is you will be locked into Seatool for their ports and domes.