Ars Technica posted a review on GarageBand for iPad
When Apple announced the new iPad 2, it also announced two major new content creation apps for the platform: iMovie and GarageBand. iMovie is an extension of the iPhone app that Apple introduced with the iPhone 4 in 2010, adapted to the iPad's larger touchscreen. But GarageBand is a completely new app that brings a slimmed down, slightly re-imagined version of Apple's entry-level audio recording software from the Mac to the iPad.GarageBand for iPad: a killer app for budding songwriters
