That they are so reliable with uptime. There really isn't anything not likeable about them! They have made our development much easier now that we stream information via Webhooks instead of just querying an API directly (which sometimes leads into errors). No major downsides at this time but I do suggest working closely together if you will be using some kind customization because there can occasionally get lost or forgotten along the way when trying work out customizations - especially outside your initial project plan / scope estimate which could lead towards delays due cost reasons as well :P The developer tools provided by these guys makes setup super simple once set up properly too ;) Checkout all options possible within both services before making any final decisions since what sounds good over email may very rarely end up being useful depending who's looking after each side!! The best part about pubnubs was that I could access my messages even when i am offline! Sometimes you get disconnected while your friends are still typing but not with this app!! This has really helped me stay connected all day long without worrying if someone will read those important emails or texts. Nothing at least so far as I know because its been working great since we started using them over 2 years ago now. !