I'd have to agree with the Protec. Although it's starting to get somewhat worn down, it's sustained a ton of abuse (as mentioned earlier, you'd be amazed at how I....err....some of these people treat their instruments!!
Actually, most of the damage on mine was NOT self-inflicted, I'm proud to claim). The pocket on the side also stores a LOT of music. The only issue with that being, after awhile the weight can start to get rather extensive! :)