How does Piwik compare to google analyics?

I have two questions:

1: How does Piwik actually compare to google-lyics?

2: If I want to monitor multiple domains, does this mean I have
to install Piwik on each and every domain?

Thanks

I have answered several different people here with issues on GA vs Piwik.

Bottom line its comparable in many ways has advantages and disadvantages. No two analytics apps are alike 100% but this at least allows you to take ownership of your own data and not have potential sampling issues and time delay issues, or require you to creat a gmail account.

Some people find piwik captures data similarly some feel it captures alot less. It depends on the metrics one looks at and the type of install(The CMS also can have an impact as people often find there are alot of pages that are things like bots, rss feeds and such that GA might capture where piwik does not.)

Piwik only need be installed once and allows you to track multiple domains via that one install.

My 2 cents enjoy.