I lost enough interest in Facebook and all the bad they were doing, that instead of downloading their chat app, I unloaded the Facebook app. Very liberating not having Facebook on my iPhone or iPad. I actually checked Facebook on a computer today -- first time this year I have checked the wall.
Actually, I didn't unloaded the Facebook app (yet) but since they split the two apps, I use the mobile site instead of the app when, once in a while, I need to peek at my wall or chat.
If you're really worried about running Facebook's software, you have other options. Because Facebook chat servers accept the standard XMPP (aka Jabber) protocol, any XMPP client can use it. There are a lot of other iOS apps plus Messages/iChat for Mac that can use Facebook chat. I primarily use Messages on Mac to talk to Facebook friends.