This product works AMAZINGLY for it's price, it sounds pretty great, and is pretty flexible, you get to connect everything to it in either mono or stereo, get individual controls over 8 different channels, and global visual feedback (not per individual channel).
I do get a bit of hissing on high volumes, but I can't tell if it comes from the RX, my synths, cables or interface.
Overall I'm really happy with it, and it was a great way to get all of my synths and more into the instrument jack of my interface for dirt cheap!!
Highly recommended if you need to get many channels into one output without breaking the bank! :)