Okay, just back from the dog walk with the 200v, and I tried both the hybrids and the T400 foamies. Of course, the silicones let in a little bit more street noise, but to me, SQ is better with the foamies on these phones. Not that they sound bad with the silicones (to me, at least), but I favor the Complys.
To answer your question, like any in-ear phone, they pretty much block out most transient noise. You can hear a bus go by, for example, but these phones are not like wearing ear buds. The definitely isolate, so I am not sure what to tell you. I walked around with them safely (in a busy urban environment, use your eyes as much as anything when walking with headphones, and keep your hear on a swivel).
I know this doesn't answer your question really, but to me, you are not going to get an "open" sound with in-ear phones. Some (Etys, W3s) really block out sound, and others do it pretty well. But hearing the outside world with things stuck in your ears isn't really happening.
As for the ep630/cx300 comparison, I find the 200v treble and mids to be clearer and cleaner, and the bass, while pretty decent, is not flabby compared to those two phones (esp the CX300).