Give us a shot... http://close.io/

We've also got an easy migration tool for any existing Highrise users: http://close.io/highrise and a solid REST API http://developer.close.io/

Check us out at http://nutshell.com — we've got a one-click import tool from Highrise. We're an established, profitable company focused on CRM with gorgeous UI.

We're polishing up our new JSON-API-based http://jsonapi.org/ REST API, and we've got a well-supported JSON-RPC API published at http://nutshell.com/api

We use Capsule + Streak. We're big fans of streak, but it's a baby CRM perfect for pipelines... we use Capsule to manage all of the other stuff. (Who talked to whom, etc.)

We just finished moving or old CRM to Highrise. I hope that someone acquires and keep updating the product.

We're big fans of Pipedrive

I'm with close.io. Don't work there, just a happy customer.