They are roughly the same, similar features with different names for some of the modes. The Q400 has some features that the RJ's don't have like coupled Vpath. You pretty much fly every approach like an ILS in the Q400 except circling approaches in the FMS database. There will be a glide slope/path to almost every runway. I've used both and there were things i liked about the automation on the Q400 and things i didnt like. As mentioned before, it does a crappy job of tracking the LOC. The Q400 is capable of single engine CATIII.