I have used act, sales force, high rise, batchbook, SugarCRM and a few others, but Nutshell blows them all away on balancing ease of use vs customizability. My sales people learned how to use it in a day and arent fighting me. Plus, they do weekly updates , so getting issues fix or a feature request added doesnt take months or years. Big thumbs up!
John Perkins about Nutshell – Small Business CRM