That looks like a really nice case, hang on that inside look familiar . . .
Who ever this OEM is they are sure getting around.
edit: Arggh why has newegg gone over from actual image files to a stupid flash based object.
Antec 300 = 205mm, cm690 = 213mm
Oh no's a whole 8mm narrower.
It might make some difference if the motherboard tray was running through the middle of the case, but as it is the 300 is wide enough to take any cooler I can think of.
If it was under 185mm wide then it'd be a different story and thoes 8mm would be important.