We're evaluating CMSs.
We've spoken at length with a number of people/companies re: general caching strategies to meet performance requirements, etc.
Drupal 7 is high on the list. If we use Drupal, our current requirements would (likely) include
Native Drupal7 ... not a variant
Varnish v3x (soon v4x) caching
anonymous & logged-in session mgmt, preferably in a distributable high-performance backend, such as Memcached.
It looks like Drupal 7 was released almost a year ago.
Reviewing the modules projects' issue cues, It appears that neither the Varnish or Memcached projects are yet ready for production. Not surprising as they appear to be volunteer efforts, with limited/sporadic funding so far.
In broad brushstrokes, is there a production-ready solution that
(1) is Drupal 7 based,
(2) uses publically-availble, widely-deployed modules that have a community of active,
production users behind them,
(3) does not require one-off, custom implementation to make it work
?
When we've spoken to several of the 'big' vendors about this, they all suggest that we deploy on their, hosted solutions, and/or hire their consultants. Again, not surprising -- but not the solution we're looking for. In the Drupal case, we're looking for community-based solutions.