Carol, my company has been using the CRM module since go-live 1.1.2014. We have also had to customize HEAVILY to make it actually functional as a barely usable CRM platform.
That said, it is working fairly well for us (now), but bear in mind, depending on how much true CRM functionality you’re after, making it function day to day, quarter to quarter, and year to year involves significant ad-hoc effort.