I participated in the beta for this, and was impressed with Billisimo. I have tried other subscription management tools, but this one just looked and felt lighter and easier than the others. Maybe it is the design, maybe it is that it does just a few things really well - it just somehow seems to come together really nicely. And, it is geared towards not just managing subs, but providing data in future iterations.
Excellent way to keep track of subscriptions.
None I can think of.