Boomslang, you're from Canada right? As is KevinS and it looks like our friends from the north are taught a different safety factor for rigging than what we are taught here in the States. Does that make it wrong? Not at all, as long as you understand the principles behind the teachings and from what I've read, you guys are doing just fine.
Thanks for posting the link. This is a very good discussion, but I don't want to take away from David's XRR thread.
Oh yeah, I own 5 XRR slings and they go out on every job I have, whether I need them or not. Standard part of my rigging kit.
My xrr slings come out every time my porti does and I guess even more than that, there great my #1 rigging tool, aside from rope of course.