I just completed this yesterday, using a laceweight blue faced leicester / silk blend yarn. I really like the squooshy feel of the cowl fabric that's created, and I found the pattern reasonably easy to follow with a lot of supporting information contained within.

I'd say that the pattern is very clear and well laid out, with good photos to show the special stitches in more detail. I do have a couple of small issues with how the pattern is worded:
1) Exactly where to place the slip stitch at the end of each round could have been explained a bit better in the written pattern, although there is enough information in the chart to work it out.
2) When round 1 is repeated, the wording isn't 100% correct when compared with the chart as you're no longer working into the foundation round.

However, once you finish one repeat and get the feel of the pattern, these niggles don't really matter any more, and it's plain sailing to the end of the cowl.

NB: Since this review was posted, the pattern has been updated to take into account the comments about the round 1 wording. (Gemma)