I'm glad we are getting more impressions, especially about hardware buttons. This is a very subjective matter, and it's hard to judge or to form an opinion based on experience of just a few people.
I have a feeling in future updates light will be optional, but personally I really like it. It's a very soft blue light, more intense in the middle where led is and fading to the sides through a lightpipe. While X7 is powered on, light stays on. When you are charging X7 - light is blinking. I would go as far as saying, I wish it would be multicolor (wonder if it's RGB leds that could be adjusted?) where for example it's blue when idling, green when music is playing, and maybe red when battery crosses 20% threshold. As Tamal mentioned, makes a nice soft night light too.
Here is my opinion about the buttons (keep in mind, MY PERSONAL opinion). I'm a diehard Galaxy phone user, Volume buttons on the left side, Power button on the right side, and my phone gets a lot of mileage throughout a day. When I use AK120ii, transport buttons on the left side, when I use L5 Pro - transport buttons on the right side. When I use Cayin N6 - volume buttons on the right side, playback wheel-click on the left side, and with N5 - volume on the left side, playback with screen off underneath. With FiiO DAPs you have volume on the left side, and power above it. If you use one device for awhile, you get used to it and operation becomes a second nature. With X7, my brain goes into smartphone mode where volume is on the left side and power is on the.. ergh, the same side, not the opposite side like in every Galaxy phone used in my household.
But this is all part of a brain burn in, I can get over it. Symmetrical location of the buttons is where the problem due to my grip of X7 (I don't have big hands, and this is hefty devices, so I exercise a stronger grip when handling X7) which results in me pushing buttons symmetrically on both sides. So I have to remember to take my index finger off track skip buttons when I'm adjusting the volume, and vise versa. The same when turning the screen off with a power button or pushing play/pause. I don't expect everybody to experience the same problem, and clearly a number of people already expressed it's not an issue for them, but it is for me. That is a reason why I'm looking forward to a case where perhaps there going to be a cutout for buttons making them slightly recessed which should mitigate this problem for me.
Furthermore, hopefully in a future fw upgrade, they will implement support for in-line remote control. Right now you can't change the volume or play/pause tracks with in-line remote control (using Android specific cables). Also, when paired up with bluetooth headphones, you can only change the volume remotely, but can't play/pause remotely yet. I'm sure it's a limitation of the current firmware and will be fixed in the future. Being able to control the playback remotely will eliminate a need for hardware transport buttons when you are using headphones with in-line remote or wireless.