I've been using the CII log/ranking pages to record my best times, but I don't find it useful for keeping track of workout performances. For that I've been using egscores.com. It allows workouts entered with intervals, and it has a graphing function, similar to CII's.
I was just wondering if anyone has been using it, as well as pointing it out to anyone that might be interested:
http://ergscores.com/