Zoho CRM is a new entrant to the SaaS CRM market and is gaining a lot of interest I believe because of its low cost, and its relationship and integration with the Zoho suite of online SaaS applications. Its feature set seems to be primarily focused on sales force automation (like Salesforce a few releases back) and has some basic features to extend and customize its features and functionality. Updates like many of the Zoho applications are frequent. 

Pros: low cost; integration with Zoho apps; unique features such as online spreadsheet integration; good choice as an entry level solution. 

Cons: little or no extensions or 3rd party support, basic APIs, functionality geared towards small teams.

Overall for workgroup CRM, or for small companies with limited workflow customization or system integration requirements, Zoho CRM is a great choice and offers great value (first 3 users are free!).