This is the second Mark Bass cover I've owned (the first for the CMD 121P combo).
They are both exceptionally well made. Stitching is top notch. The fit is pretty tight. The handle holes line up perfectly.
The material is tough cordura, and has a good amount of padding between the layers.
It's not going to offer the protection that a hard case will, but it doesn't take up anywhere near the room when not in use, not does it weigh as much.
If you're going to spend several hundred pounds/euros/dollars on a speaker cab, spending a bit more to protect it is a no brainer.