I like that they make it easy to get started with them, but also have options such as premium memberships if you want more features or advanced settings etc.
They are always adding new things so there is never anything not working right now! If their customer service was better people would probably be using this site even less than what we do already (which isn't much). We use etiology in our business because of all its benefits compared to other similar sites out there - ease-of-use being one big plus point.