None of them have the polish and stability of Meebo Messenger, I don't know what criteria for "better" they excel at.

There's also Google Talk in Gmail/Google+ ;)

Speaking of google, when the hell are they going to release a GChat app for iOS? The GMail web page on iOS doesn't have GChat, so I went searching for an app on the Apple App Store a while back and found one. I'm pretty sure it was just a UIWebView wrapper which sent a different user-agent to fetch the desktop version of GChat, and it wasn't long before it broke (I think google had changed the GChat URL).

it's just xmpp, just download an iOS XMPP client and you're all set. Same with FB chat.

You won't get push notifications without turning over your Gmail credentials to a third party. Google handles that for you for the official Android client. I only do it with application specific passwords and two factor authentication, but it's still an annoyance.