Drupal as a service

Hopefully this is an appropriate discussion item for this forum.... I've been increasingly interested in finding out more about two of the Drupal as a Service providers, Lullabot's Buzzr and Acquia's Drupal Gardens. Anyone with hands-on experience with either or preferably both, that can provide some insights and comparisons? I know that DG runs on D7, but can't find a definitive version for Buzzr (D6 or D7). Anyone know? Also what is the downside to either or both of these services, other than they cost $$$. Thanks in advance for any feedback....