I used Cage and was successful...but research every company and find what works for your specific circumstances, and which one is recommended for the particular airline you are targeting. Overall, they present the same information and all are very helpful.
Personally, I wanted face-to-face prep as well as availability via FaceTime, and not a cross-country jumpseat trip away. My partner (also successful) did not want to travel, and used Clark consulting, as everything was offered via FaceTime/Skype. While we learned many of the same things, they were presented very differently. I had a friend use emerald coast, and she said that it felt like it was geared toward military personnel transitioning to civilian aviation. And I had two friends use centerline, one successful, and one not (for a given airline).
While mostly the same information is learned from all of these companies, research every company, and talk to them about the services they offer, and see if they are a fit for you. Research their success rate with the airlines you may be targeting (many of these companies have pilots and/or former recruiters from your desired airline working for them.) And be sure they provide the exact services you feel you need, and in the most accessible way for you. And honestly, you get out of it what you put into it.
Good luck! You've probably spent a ton of time and money on building your career so far, interview prep is worth every cent!