I don't check this forum too much nowadays but I happened to check and see this post.
Yes, I've heavily used PlayerIO since around late 2012. I use it in my MMO Flash/AIR game called Helmet Heroes. I still use it to this day in the game, and the game has made me a living since around that date and continues to do so to this day. So I have a ton of experience with them. IMO, I may be one of their most major users, as I'm not really sure of any real big games using their service. Collectively, I've paid them quite a penny over the years.
Their AS3 API should still work fine, my game hasn't broken or anything and is still operating as it should, so it's doubtful it's busted or anything. I don't actively develop my game anymore as far as updates go, so it's been chilling mostly since 2018 but still ticking away strong. My game reaches a max of around 1,500-2,500 online concurrently each day, usually at night.
The service works as it should, and it makes making an online multiplayer game significantly easier, especially if you're someone just getting started in multiplayer like I was back in 2012. I started another MMO using Unity in 2018 and started using them again for this second game as well. After several months though, I shifted away from them and decided to try and make my own server code with AWS, which (after a lot of initial work) is proving to be a better solution. I could say a lot, but here is my breakdown of them.
Pros:
-Makes making an online game significantly easier to understand and quicker.
-Includes things like Paypal integration, Google Play, IOS, and such also alot easier.
-If your game gets big, it automatically handles running and expanding servers, etc.
-Can also handle logins, etc.
-Just about everything regarding your online stuff is all stores in one nice place on their website.
Cons:
-A bit limiting. If you'd like FULL control over everything, their service can be a little limiting once you gain more experience. Not a huge deal, but something to possibly consider.
-Expensive. With a lot of traffic, their price is quite a bit expensive compared to writing and managing your own servers and such vs something like AWS.
-Extreme lack of activity. I could say a lot regarding this but to be short, the platform seems rather dead. There is next to no activity on the forums, or posts from admins, or updates, etc. Seemingly from my perspective, there is one staff member I've ever interacted with that seems to handle things. He responds to email, although not in the most timely manner. I've always felt the service was going to die because of this, but nonetheless it always keeps going year after year. Like I said, it usually works as it should, so I guess it does what it's supposed to. It's just not comforting seeing little support or updates.
My final verdict? If you're new to multiplayer games or if you're making a smaller game use them. If your experienced writing client-server communications for games and you have big ambitions for your game, make your own solution using something else. If any questions, feel free to email me at robby[at]eliatopia.com