ApolloPad is still pretty new. We have a few hundred thousand words written using it so far, but we have big plans for it and a long way to go to reach them.
ApolloPad is now in public beta, meaning that anybody can sign up, and we are still expecting a few bugs to crop up, but those should be fairly minor. We aren't charging for use of ApolloPad yet either.
In the meantime, if there's anything you'd like to see from ApolloPad in future, let us know in the comments below or email us at firstname.lastname@example.org!