Acquia

Acquia was founded by Drupal’s creator and sells a managed platform for running Drupal, which makes it one of the better-known names in that part of the market.

Criterion 3 — public pricing — fails. The pricing page publishes no figure for any plan. Every route from it is a “Learn More” link or a demo request form, and a price arrives only after a conversation with sales, which also puts criterion 2 in doubt.

Being well known in Drupal does not carry a record past a criterion the register applies to everyone. If Acquia publishes a price for any plan without a login, this reverses.

Drupal itself is open source and runs on any provider here with PHP and a database.