Pivotal can handle much more data and is much more geared towards to agile. I like it to handle my tech project management. Its brilliant for that.
I use Trello for "business project management" (marketing copy, emailing people, customer development todos) and pivotal for "technical project management".
I use Trello for "business project management" (marketing copy, emailing people, customer development todos) and pivotal for "technical project management".