Well the more traffic a site has, the more resources we need to process that traffic. 500,000 daily page views is currently the max we allow to ensure our service runs smoothly for everyone. This limit is higher than most other analytics services allow, and easily covers 99.9% of the sites on the internet.
It just seems like Clicky is more focused on giving "easier" to grok numbers than GA, and makes it a little harder to get some of the more custom numbers.
Fair enough. But that's also one of the reasons we're successful, because we make stats/analytics easy to understand. GA is a very powerful piece of software but it also has a fairly steep learning curve. A lot of our users are ex-GA users who stopped using GA because they just didn't get it.
We have plenty of users who use both Clicky and GA together though. Clicky does "most" of what people need and they like the real time aspect, but when they really need to dig deep into complex analysis, that's when they hit up GA.