We have been using Capsule for over a year now. Overall, it is a GREAT entry-level CRM, and the integration with Google Apps is perfect. The only issue we have run into is the filtering interface to generate lists of our clients based on time constraints. For example, we have no way to see a list of companies we have not contacted in more than 30 days. While their e-mail support is always timely, they will only accept feature requests through UserVoice, and in a full year we have not had any luck getting this essential feature added.
The only other feature we see this missing is better duplication detection for organizations and users.
To summarize, this is still our favorite entry-level CRM based on its clean Google Apps integration, but we have had frustrations with the filter system.