As an external sound card and headphone amplifier it has met my expectations. It is my first time to own such a device. I don't play games, but need it for music and movies. I have read some reviews about the difference with E5, and the amplifier compared to Fiio E10K. I am glad the review on Slickdeals was accurate, that the amplifier is good enough. The output impedance, as one article said, could be lower, but in my experience the max volume is good enough (I use it to drive both HD650 and a Bose Companion 2).
My input is the computer (foobar2000 with wasapi, kodi and other movie players), and a portable CD player. It is easy to toggle the direct mode/off but I do wish there is a tray shortcut.
The best thing is that line-in works when USB input is enabled. When I want to listen from the CD player, I don't have to unplug the USB input.
(forget to mention the device selection in either Windows 10 or in foobar2000/kodi also makes it very flexible.)
Initially my biggest concern was the delay as a USB device. I had a $5 USB sound card before, which was quite unresponsive or had jitters. But I found this one plays instantly.
One issue in Windows 10 though is the device stops working after computer resumes. The light flashes and I have to unplug it, plug it, repeat maybe several times. Once it starts to pick up the signal then it would continue to work without problem. I don't think it is a hardware issue, just the driver fails to initialize it properly.
It does not work well with a Mi-box (an Android TV device). There is loud crack sound once in a while. It works in Fedora Linux without such issue.
It is quite small, not bigger much than a pack of cigarettes. I got it for $75 at Best Buy clearance. I'd like to buy another one to avoid carrying it though, to reduce the work of setup, and to avoid repeatedly plugging in the wires. Somehow I feel audio devices are more delicate.