I bought the Bluefin Pro for the Sony CX550 but that was also because of manual dial which let's you control things like exposure. Not sure if that dial works for the Canon camcorders.
And the color, don't forget the color!
Sorry, I could not help it...
Actually, nobody can understand that joke anymore, since both housings are black. Oh, well.
This being said, for what it is worth, I am using the previous incarnation of the "Standard" Bluefin (used to be called the Stingray G2+ a few months back...and was gray), and I am perfectly fine with the LCD. My feeling is that behind a thick piece of glass (mask), a foot of water and limited light, you can't figure out the details on a 3.2" OLED or a 2.7" LCD screen anyhow. But I may be wrong... :-)
I would in retrospect agree with Peter that the hydrophone might improve things, as the metal housing does damp sound a lot.
Manual controls are accessible via the left handle on both housings, but that's maybe not an option on the Canons?