A major issue with it is it's so old it's IP addresses are in a fair number of blocklists. I believe it's well over 20 years old. They also have a lot of old school services like ssh tunneling, Usenet, and anonymous remailer access through pulldown menus so you don't have to mess with a remailer client. And they come with free email (and a time-limited throwaway email generator) and a bit of web space.
You can get any of these elsewhere, but not many places will give you all this for $5.95 a month.
Note, I haven't used this service since the early 2000s, but I believe it's still under the same management, who knows what he's doing.