Hi Leon, welcome to the forums - I'm not sure what that first reply meant
Ok, to your question: I reckon there's three things you should consider...
1: High ISO sensitivity performance
2: AF under dark conditions
3: Anti-shake for slow exposures
In terms of high ISO performance, both the Canon and Sony can go to 1600 ISO, but the Canon produces cleaner-looking, better quality results.
In terms of AF accuracy under dark conditions, both cameras have roughly the same potential, which means it's down to the particular lens you attach. If you use the kit lenses, I don't think there's much between them. if you upgrade to a brighter lens though, you'll enjoy superior focusing under dark conditions. For example, the Canon EF-S 17-55 f2.8 is a great lens for shooting under dark conditions. See our review here:
In terms of Anti-shake, the Sony of course has it built-in, whereas the Canon requires Image Stabilised lenses, such as the one mentioned above.
So if you were comparing the kits, you're really weighing up the Canon's high ISO quality against the Sony's built-in anti-shake. Remember anti-shake whether in the Sony body or a Canon lens though are only effective with static subjects. If the subject's in motion, you'll still need a fast enough shutter to eliminate any blur.
If you're really serious about shooting under dark conditions and have a higher budget, I'd recommend considering a lens designed for it.
Let us know what kind of subject you're taking though and we may be able to help more. Will you be using a flash for example? Do you have existing pictures which are either shaky, noisy or out of focus? Which of those three is the biggest problem on your existing shots, or ones you've seen?
Hope that helps!