I'm the CTO of a 42 year old Software Company.
We started using DOS ACT in the early 90s moving to Goldmine and back to ACT around 2000. We've used ACT 2000 until 2009 only to get the data into SQL Server. Recently we moved to 2012 because 2009 wouldn't support modern browsers and Office.
I can't financially get our staff off of ACT being we've customized it to our needs over the years and all our back-end systems interact with it.