I'm personally not familiar with either model. Although I have handled/shot Ikelite's briefly.
So I'll just point out some differences off their websites.
Ikelite weighs 8#/Equinox 15-22# - going to travel with it? (I should talk, I carry-on an EVO...lol)
Equinox offers an optional monitor back. Ikelite offers their side-mounted mirror with reversing circuitry. This may not apply to their SR12 housing but I did read a post in which an Ikelite owner described that when he switched on the reversing circuitry, other LCD functions were obscured/difficult to use. So he'd do his adjustments first then switch back to it to pan.
Seems like more work, but it's unclear if that's still better than Equinox's option - if they even have one - for viewing touchscreen adjustments. Most external monitors use the composite/component out and unless they've done a good job of re-engineering, the actual control change made on the LCD aren't reflected on it. I do think you would see White Balance changes after they were made however you might be accessing the controls blind - I don't know.
L&M provides a small viewing window on the Bluefin for just this reason in addition to their monitor back.
And on some housings, adding an external monitor limits the size of the extended camera batteries that can be used.
Also unless the Equinox monitor is Hi-Def, which I kind of doubt for $250 - you may want to use the camera's LCD - esp for macro work. Although that's probably a wash since it's farther forward on the housing and being reflected through a clear box on the Ikelite. Including your mask you're probably a good six inches from the mirror best case.
In bright sun that could be an issue - maybe someone here with an Ikelite mirror can comment? Since the mirror is hinged, I'm guessing it's not hooded.
Ikelite seems to offer more port/lens options - I couldn't find any ports listed on the Equinox site yet they do offer optional w/a lenses?
Ikelite offers full Manual White Balance and WB Shift control - does Equinox? It's possible that Ikelite also offers full camera control via your touchscreen. In case there was something you wanted to change u/w - I know there's times I've wished I could. Once I accidentally left nightshot on - whited out the whole dive...
Does your SR12 offer focus control through the touchscreen? That could be useful doing macro.
Equinox goes 50' deeper - 250' vs. 200' for Ikelite if that's a factor in your diving.
hth,
We have both an
Ikelite forum and an
Equinox rep on SB now for help in getting answers.