dinner rollwrote a review of Black Diamond Camalot X4 on February 27, 2014
Familiarity: I've used it several times
I'm writing this because I disagree with a number of comments that other people are making. The small (.1-.3) sizes really aren't single-axle cams. The axle-centers for opposing lobes are offset in the same way as for double-axle cams (just not completely separated), which allows for a greater expansion range for a given cam angle. The difference is noticeable- the yellow .2 actually retracts to be as narrow as (officially a bit narrower than) the purple mastercam.
As far as I can tell, the only significant and objective differences between these and the mastercams are the greater expansion range and stem flexibility (especialy for horizontal placements) of the X4s. The head width for the X4s is marginally greater. The cable guards seem like a good idea. I don't know about the steel wire vs kevlar cord; it probably doesn't matter much.