ShotOne
Have a look at the USAf Safety Center stats for:
MQ-9 Reaper
http://www.afsec.af.mil/shared/media...121210-021.pdf
MQ-1 Predator
http://www.afsec.af.mil/shared/media...121210-019.pdf
NB: the USAF use a rate figure per 100,000 flying hours instead of the UK's more common per 10,000 flying hours.
So from the stats I see that in 2012 the accident rate where Predator was totalled (ie. Cat 4/5) was 0.42 per 10,000 flying hours and for Reaper it was 0.34 per 10,000 flying hours.
I can't see any reason why these are not favourable and comparable with manned aircraft stats???
iRaven