I've benefited a lot from CF.
It has taught me to pick my battles better.
It has helped me hone my argumentation and persuasive skills.
It has helped me learn to communicate my meaning clearly.
It has challenged me in various doctrines which I eventually ended up changing my mind about. I've been exposed to many and varied differences of opinion and facts I was not aware of that have caused me to grow.
I've learned to be careful not to fall into the trap of getting entrenched in my position instead of being open to considering another one. (This is an ongoing process, lol). And I think this is key if we want to have fruitful debate/discussion. I've learned to be careful not to strawman the opposition, to let people tell me what they believe not try to learn what they believe from someone who agrees with my preconceptions. (e.g. read "Love Wins" or "The Shack" instead of reading a critique of the book by someone I like; don't start a post/thread with "WoF believes X", instead say what I believe and let WoFers speak for themselves [of course, I don't debate about WoF anymore, see below]).
Arguing/debating/discussing online has revealed a lot of myself to me. How I react - whether it makes me angry, sad, frustrated, happy, proud, etc - shows me things in my heart that I didn't know were there.
Yeah, sometimes it gets to be too much and counter-productive. When I realize that my anger or frustration at someone online is affecting the way I treat my loved ones.... that's a problem. But that happens less and less all the time.
I don't post and visit the SF/C subforum as much as I used to. I used to be really active here. But it seems like the regulars here are stuck in a rut of the same exact arguments that have been being argued here for years. When the same people are arguing the same thing FOR YEARS that can't, IMHO, be considered productive. Especially when past "wrongs" against one another are brought up again and again, hurt feelings and unforgiveness are allowed to fester and people can no longer see one another as brothers and sisters because our doctrines divide us. There aren't any new arguments or counter-arguments. Everyone knows how everyone stands on the matter and the arguments turn into snark-fests.
So, yeah. Overall, I think CF has been good for me. It's not perfect, but the strife and pressure causes growth, too.