I had a pair of HE400SE that I recently sent back but the build, while probably on par for a pair of $100 HP, was good with no issues. I also knew about HiFiman qc issues so I curbed my expectations when I clicked the 'order' button but again, I had no issues with my pair.

However, I did not care for the sound of the HE400SE HPs. Not that they were that bad but I was just unimpressed. Nothing stood out to me across the board as special so I had little motivation to pick them back up again. I tried several dac/amp combos with the same results.

I do love my DT 770 Pros though. I will never get rid of those and if they ever break, I will order a replacement.

Cheers!