I think the argument about the iPhone backdoor software is a slippery slope one. As long as the judicial system use mandates and the process is transparent, I think you can't really complain. This is what Snowden is about.
We're talking about homeland defense here, the Islamic State is on the rise, so I would be careful when defending Apple here.
Now I'm not a lawyer nor a political scientist, but I want to side with the FBI on this one. I'm sure Apple is playing their popularity card here. There are things that are more important and go beyond gadgets built in the silicon valley. It doesn't necessarily have something to do with Snowden.
I expect people to disagree with me here, and it's fine.