I think where this might fork a little is consumer vs enterprise. Dropbox is meant to be understood by a much wider audience than Heroku. For a consumer facing company being easily understood makes you much more accessible to many more consumers. It also makes your service more memorable when your name is: simple, appropriate, and conversation-optimized.

"I'll put it in the Dropbox tonight."

If you treat this as an equation, you want to increase: % of people that 'Get' what you do (off the bat), and % of instances people can easily recall your name, the next time they have that problem you solve.