My 500k update on er9. I’m pleased with it. It works very well. No issues, despite a few rides in really grim weather conditions. I’ve also washed the bike quite a few times now. No problems.
I’m interested to know if someone here can compare it with other electronic groupsets. I’ve only ever ridden the last generation 11sp Ultegra Di2. But that’s quite a while ago. I wish the shifting was a bit quicker with er9, particularly when going to bigger cogs/easier gears on the cassette. The time it takes from clicking to the chain making it to the next cog sometimes feels rather slow. Especially compared to the mechanical groupsets I got on my other bikes. Also: More feedback from the shift buttons would be nice.
Other than that, no complaints.