Originally Posted by
ThatT1Feeling
I think it's more predictable, especially if you are transferring from a Domestic or are registered for IRIS. Of course, in theory FCC could be quicker but appears to be far more likely to be completely horrible than the seamless experience promised.
Why would you want to go airside when "transferring from a Domestic" given that you don't have to go through security, assuming your domestic flights has arrived at T5?