I just used up some Kidsilk Haze to make the Ice Queen from Knitty. I thought it was lovely to work with, deifnitely not as slippery as a lot of lace-weight yarns can be.
When I first started the pattern, I got about two inches in and had to rip it out. I let it sit for a couple days out of utter fear from what I had heard...
Upon getting the courage to frog, I found it was actually really easy to rip out. I had absolutely no trouble at all, so I was ecstatic. I did hear though a rumor somewhere that if you have trouble ripping it, to put the project in the freezer for a while, then rip it out. No idea how or why it works, and I haven't tried it yet, but I have heard of it.
Good luck with the shawl, I'm sure your sister will adore it!