My success rate for completely-working-out-of-the-box BGN cameras from KEH is 50% - I bought 2 x Pentax ME Supers from them, both in BGN condition - 1 is just fine, some wear on the body, but mechanically and electronically great. The 2nd had meter problems and ultimately the shutter would only fire at 1/125 no matter what the mode selector was set to. Rather than send it back (the camera was just under $100, and cross-border shipping is a bit of a hassle as others have mentioned), I had a local repair guy fix it - he basically completely overhauled it for under $100 - so, for just under $200 I've got an ME Super that will work for years to come, and as a bonus comes with a local warranty from my repair guy.
So, just my opinion, but if you're really concerned about it, shop around locally - there have to be a lot of camera stores and/or camera repair shops that sell used equipment in Toronto and area. Buying one locally may cost somewhat more, but if something goes wrong you can take it back without dealing with shipping hassles, etc, and you can know exactly what it can and can't do.
For me personally, I would definitely consider buying from KEH again, and I do browse them regularly. I haven't found any screaming good deals like the ME Supers yet, though