I love Planet Waves cables-- at least in comparison to Monster.
If you compare the quality between the two, I think Planet Waves is the clear winner. Maybe Monster is getting better, but a couple years ago I compared Planet Waves and Monster cables. Monster cables just appeared to be plain old generic cables that are made to look a little more "flashy." They didn't appear to have any extra strain relief or anything like that-- just a generic over-priced cable.
Planet Waves cables have double molding, double shielding, and double insulation. To me, that means a better cable.
I agree that a downside is that Planet Waves cables cannot be repaired. BUT they do supposedly have a lifetime warranty (I haven't tested that yet-- haven't need to). So, in theory, you can just send them your bad cable and they will replace it with a new one. Of course, this would be a problem if you are in a time crunch.
Yes, Planet Waves are kind of expensive (check Ebay, you can get good deals). But if I'm going to buy expensive cables, I would much rather buy Planet Waves than Monster!