What does the software or service do well? The software does a great job of simplifying CRM. I've used a couple of CRM's in the past that were so complicated that its purpose was lost.
What does the software or service not do well? Some of the terminology can be confusing/misinterpreted, particularly under a specific Customer Account with the 'Activities' vs. 'Task' once you've become more familiar with the system then the differences are clear. However the two terms are so similar that it can easily lead to immediate confusion.
What do you wish you had known about the software or service before using? I can't really think of anything. As I said, it's the most user friendly CRM I've worked with.
Have you used a competitor to the software or service? If so, how does it compare? I have, though the names escape me now. They seemed to be directly designed for Real Estate Agents and honestly I could not stand them. I am often tasked with learning new portals/websites and generally speaking am able to pick them up quickly and easily. The CRM's I've worked with in the past would be an exception to that. I never could get to the juxt of what they were actually doing. Really Simple Systems takes the guess work out and makes the process transparent and easily traceable.