The most useful thing about revboss has been their automated email follow up system that allows us to send emails at scale without having to do it manually each time! I wish there was more integration with other tools (like HubSpot) but this isn't something we're looking into right now.
If you are serious about building out lead generation campaigns then rev boss will be worth it if they have good content or offers for you in terms of selling them as an add-on. Also, the reporting aspect can sometimes get overwhelming so make sure you know what you want before signing up - otherwise you might end up wasting money by not knowing how to use everything properly/efficiently. Lead scoring & nurturing with our CRM via automation using Salesforce Marketing Cloud.