It's a nice player but I would not make it my main player. Compared to lets say the I Basso DX 160 or the Hiby R5. One there are no apps. It says Wi-Fi but that's very limited it's only really for downloading updates. The Bluetooth is extremely weak for TWS (True Wireless Headphones) . The O/S is definitely entry-level this thing doesn't even have a clock. I know that's minor but it just shows you how much they cut corners to get the tubes in at a cheaper price. I've also had some problems with mine. I'm not sure if that's with every player but I do have a lot of freezing it plays for an hour or 2 then freezes up. I've also had issues with the file location being lost. You'll be listening to music and all of a sudden there's no file. You have to reload everything. It doesn't take long but it's frustrating.
The plus side is the Bluetooth works really well when pairing it up with the phone. That's the real strength of this thing works great as a DAC for the phone. Also as a line out to a standalone stereo system. There the sound is amazing. The tubes sound really good they give you 2 different sound options plus the solid-state option without the tubes. If you do TWS you can only use solid-state you cannot use the tubes. If you are using as a Bluetooth from the phone you have to use wired headphones. The Bluetooth can only go one way you're either streaming from the phone or you streaming to wireless headphones you cannot do both. So I think this is for an audiophile who already has a really nice player. And has a lot of really nice wired headphones not relying on TWS. For example I have the Hiby R8 it's a fantastic player but it's a little big and bulky to carry around. So this hit the spot it's easy to carry around and I can easily use it with my phone and I do have a micro card so if I'm not in a place to stream I can listen to music on the micro card. So again if you already have a nice player and are looking for something with the tubes sound that is a little cheaper this could work for you. But as a standalone player no way look at the I Basso DX 160, the Hiby R5 or the Fiio M9. All of those players are going to give you a much better all around experience compared to this one.
It has warm and musical sound. I usually listen to balance output but the down side it uses memory instead of streaming music so it acts as a Bluetooth with amplification.