I have both the Black Tarp and Black X versions of this bag. My review of the Tarp version was 4-stars, because the zippers can be difficult to open because the material of the bag is so stiff. My review of the Black X version is a full 5-stars, however. The material is lighter and thinner than the tarp, and thus more flexible. The zippers work incredibly easily. It still has the same organization features and room of the Tarp version, but it's just a little lighter to carry.

Of course, there is a downside to the lighter material, but not enough for me to take any stars away, as it is to be expected that the Black X bag will not be nearly as water-resistant in the rain or snow come fall and winter in the Intermountain West.

So while I am using the Black X currently, come wetter weather, I will be switching back to the Tarp version, especially as my gear-bag for my days at the Utah Cyclocross Series. It's just a no-brainer.