Older e8000 was super reliable, ep8 so far seems to be reliable, e6100 had lots of failures.
Both newer motors are more efficient and notably quieter than older motors for sure (identical to bosch g4 cx/crg now). As mcamb says, you quickly get used to what you have and don't worry about the other options, most folk can only tell a difference if you put them on different motored bikes back to back in the exact same bit of road.
Older e8000 was super reliable, ep8 so far seems to be reliable, e6100 had lots of failures.
Both newer motors are more efficient and notably quieter than older motors for sure (identical to bosch g4 cx/crg now). As mcamb says, you quickly get used to what you have and don't worry about the other options, most folk can only tell a difference if you put them on different motored bikes back to back in the exact same bit of road.