What is recommended for boats from Santorini to Mykonos? Two lines Sea Jets and Hellenic Seaways are two I have found but reviews are questionable.
Have you considered flying, if budget is not major consideration, depending on dates you can find flights for 90 euros on Olympic Air, I found some for later july and its only a 40 or so minute flight.. just a thought. I have taken a few ferries and they are not super fun.. but they are cheap usually. Prices vary by departure times and dates so a lot depends on when your trip is..
I would not put much faith in reviews of ferries. You are pretty much limited to taking what is available, and in my experience, all offer the same basic service...transport. When comparing, consider first the schedule, both departure and arrival times. Beyond that, look at the boat size and consider your tolerance for rough travel. If you are sensitive to motion, the jet boats can be risky...if the sea is glass smooth and no wind, they are great, any chop at all and maybe you, and certainly some around you, will need a sickness bag. The big old car ferries are very stable, but slow. The best compromise are the large catamaran type ferries, decent speed with good stability.
Thanks for your helpful comments.