In reply to ray:
I've got a 60m serenity 8.9mm, only been out once or twice, but It's definately not an everyday rope......the sheath is very thin
It's a rope that can do everything, not one that should be used for everything. Mine's reserved for Ice (when I need a twin), and when it's really only possible to take one rope with me. e.g. I'll be taking it to El Chorro this year.
As others have said these types of ropes are skinny and slick - belayers beware. Also, it could just be me, but when using it as a single on lead, it doesn't instill as much confidence as my chunky 10.2mm
I wouldn't recommend it as an 'everyday rope' but £120 for a 60m 3-in-1 8.9mm serenity is an absolute bargain! The joker is slightly thicker at ~9.1mm so may be more resilient to wear. I suppose it comes down to how well you'regoing to treat it.