My best friend is INFJ and she's pretty awesome. I mean, like all friendships, there are downsides. Yes, she does tend to be pretty insecure, she sometimes emotionally snaps at people for silly things, and she can be kind of moody. Though, I'm sure she must have her problems with me too. I know sometimes it upsets her when I 'talk about people like they're robots,' or am far too logical.
However, since we are both pretty well-developed models of our MBTI types we are able to accept our differences and learn about each other rather than trying to change each other. I think that's a key thing to remember in a discussion like this; not everyone is a great example of their personality type. Sure there are some pretty shitty INFJ insecure attention-whores, however this is not a good example of a well-developed and healthy INFJ type. Similarly, there are some psycho bossy controlling psychopathic INTJs, but they are certainly not good models for the INTJ MBTI type.
Overall, from personal experience, I've had a really great long-term friendship with an INFJ. It's awesome to have someone I can share my Ni with who doesn't think it's crazy. It's also pretty cool to see how our Ni's work together to figure things out or predict them. I know that no matter what I tell her that my Ni is doing, no matter how far-fetched it may seem, she's always going to accept it and support it even when my SJ friends ridicule me for it. It really sets our friendship apart and above.