Ask HN: How do you track the rankings of competitors' iOS app?

Do you know some good tools to monitor the rankings of multiple iOS apps in AppStore?

Suppose a case that you are the iOS developer of LivingSocial and you'd like to monitor the ranking of competitors' apps (such as Groupon, Amazon, eBay, Google Shopper, for example) very frequently.

There are some monitoring tools such as appannie (http://www.appannie.com/top/united-states/), but cannot display multiple apps in a single screen.