I have both because:
SE2 will not see other aircraft that have only PilotAware (P3i) and
PilotAware does not transmit ADSB-out, SE2 does.
I fly with PilotAware displaying traffic on the tablet because it shows other aircraft transmitting P3i, ADSB and, with some limitations, Flarm via the OGN ground stations.
SE2 will be making me more conspicuous by transmitting ADSB-out.
PilotAware does seem to show more targets than SE2 where I operate but there's little substitute for looking out - the one that gets you probably will not have either PA or SE2!
I'm sure others will have different opinions and experiences...