A blue-ish grey is pretty accurate... They're quite vibrantly blue really if you look close. Same in ESB... ANH's are all a pale light grey color, and EU has light grey ones existing (X-Wing, TIE Fighter, comics, etc.) but ultimately no squints in the movies were that color. Go figure.
The POTJ one may be a shade or two off, but it's far more true to the films in terms of color than other ones we've gotten so far. Likewise, Vader's TIE is inaccurate blue-grey when it should be the light grey... never been fixed.