I can't say I use that particular brand (I have an Integral Designs Siltarp 10x12) but I wouldn't ever consider heading out without a good lightweight tarp.  The idea of sitting in a tent for a day or two waiting for the weather to clear is definitely not my idea of good time.  Every time I pitch hoist my tarp (because it feels more like hoisting a sail then pitching a tent) I can't help but feel what a clever lad I am.  Very fulfilling!  Seriously though, learning how to rig a tarp is well worth the time and practice to perfect.