I don't know if the keybed is the same, but I have an Oxygen 49 controller from M-Audio. I wouldn't say that it's finky - but the keyfeel is pretty crummy.

I can't say about the 'Big Piano' - you really don't need an instrument to look at the transmitted MIDI data. In fact, you should be able to just do this by recording and looking at the Event List in RB/PTPA/BIAB. Hit record on a track and walk up through a chromatic scale where you think there are dead zones and look at the event list that results. If there are missing notes, repeatably bad (upon several times through the scales), it's bad - plain and simple.

If it's intermittently bad (not the same notes being skipped), then there is a wider issue to try to figure out - could be bad USB connection in some way, some other internal issue to the keystation, etc.