UMC404HD : All in all it's a good product.

Unit does the job.

Sturdy metal casing, no loose potentiometers or knobs.

Headphones output volume potentiometer sometimes produces some very silent crackles when using it after some time untouched but after few tweaks volume up and down it just disappears and works well.

The headphone output produces lil' noise after pushed around 2 o'clock and the noise increases as you raise the volume. But it's only audible just listening to a sound card headphones output without playing any music. It's inaudible while listening yo music and I listen it around 11-12 o'clock position. You don't wan't to listen that loud anyway :) so no big problem here.

All jack input slots are sturdy. Have not tried RCA outputs but I guess they work as usual.

Connected some outboard gear to process my sounds. Latency is really low only few ms using Reaper via reaInsert or just sending sound via send to hardware and back to soundcard.

Good unit, cheap, use it everyday and no big problems to date.