I am proud to say I have been using DemandTools for around 15 years now!
I have been a Salesforce System Administrator since 2004 and cannot say enough on the difference DemandTools has made managing data in Salesforce. The tool has literally saved me time from hours down to minutes and eventually to no time at all using JobBuilder.
I have said to management and leadership "if you want to get rid of me, just take away DemandTools". And even though I said it jokingly, I am truly serious.
I just started using DemandTools V...and WOW! I am a super happy camper!