Ask HN: What metrics do you measure for a B2B Beta?

I'm launching a Beta for some B2B software this spring. I want to make sure to measure the right things. Here's my list so far, tell me what I forgot!

  * Weekly feedback surveys for the users to provide qualitative / open ended feedback.
  * Time spent using our product, per user.
  * Average time to initial response, for customer support requests.
  * Average time to problem fixed or feature added, for customer support requests.
  * Average time to generate outputs.
  * Number of inputs used per user.
  * Number of outputs produced per user.
  * Number and type of any bugs uncovered.