PCM every time!
Most interference in momentary, PCM will ignor it, PPM will glitch, which may rip your wings of you 200mph model, or even worse flip it into spectators.
You can still fly PCM even with a lot of interferance, providing some frames get through, you have control. The control may be slugish, this is the warning. PPM in that situation would have the plane leaping about all over the place in god knows what direction, and as i have said, may rip it apart.
When total signal is lost, i program mine to throttle back and hold, if you are lucky the interference will stop and you have control again, if not, the plane stays on the same tragectory but slows. PPM in this situation, well it is anyones guese as to where it hits.

I have flown Futaba PCM for 10 years and can honestly say i have only had 4 or 5 lockouts. In all but 1 of these cases i have had signal return and safley landed the plane.

i would not trust a Jet to anything else!