I love how easy it is to set-up. We are able to have phone number campaigns created and live on a website/ads within about an hour per account. We especially love the new features that have been added throughout the years - such as the ability to order new numbers immediately without having to wait the request to be approved. These help us to improve our own productivity.
Additionally, the customer service is always available and helpful. If we have a question, calling in or emailing is always a pleasant experience.
Creating users and permissions have some limitations when you're working with a main parent account and trying to give one person access to numerous sub-accounts.
1) Certain filters in reporting are not accessible for parent account users when looking at sub-account reports.
2) You cannot use the same email address within numerous sub-accounts without using tricky upper/lowercase spellings.
I wish this would be streamlined a little better for users with multiple accounts. However we have found that the user abilities are a lot more advanced over other platforms that do not even allow parent/sub-accounts.
The ability to attribute calls to specific campaigns is invaluable information. This feature in itself is very important to our needs. Then further being able to record calls and attribute context to the call is very helpful in our reporting.