Highrise was great for seed stage, but Salesforce became necessary at Series A. Highrise was super light weight and took no training. We had to transition to Salesforce, as we had multiple teams needing to access records for different reasons. It has much more detailed information keeping, and way better graphing/visualization of data.
We used Basecamp when we were Seed-stage, and it required no training. We moved to JIRA when we raised our Series A because it enables more dissemination of information and ticket tracking.