I really worked hard to attract over 60 rockstar mentors for https://mentorcruise.com. Many of them are home in common engineering topics, Web Dev, Mobile Dev, but we also have some very nice mentors in Machine Learning and Entrepreneurship (including a YC founder!)
I'm always working on improving how people filter through that list, but I'm at a point where I'm thinking that too much choice might be bad. Someone who is plainly looking for someone to help them build an Android app might be overwhelmed with the many Android mentors.
I'm actually thinking about launching a second streamlined and standalone offer. Something like 'Your personal mentor for $50/month' which would just randomly select one of the matching mentors and pair them up. What do you think?