NetSuite CRM is ok for simple and low volume use cases, but it doesn't support a lot of complexity well. And CRM is something NetSuite is just kind of maintaining. They're doing nearly zero improvements to it, so I wouldn't expect it to get significantly better any time soon. If you're a startup or small company with 3 or 4 salespeople, it would probably work fine. If you have multiple sales teams and 100 salespeople, it might fall down.
The other issue I've run into is that a lot of salespeople will revolt if you try to get them to use anything other than Salesforce since it's kind of the industry standard.