Here is what I can tell you about this:
1) I'd say in genuine RMS watts, this is about 40-80 watts RMS. Plenty loud for a small backyard Karaoke or concert ... but nowhere near the "540 watts peak power" claimed.
2) The wireless mics work GREAT, but they are very sensitive, so don't get to close if you sing loud or they will distort!! Also, they are on the same channel, so they do not have independent volume controls for each mic, just one for both.
3) The Echo is PERFECT, just a nice slap-back, that is right for almost any music ... just don't use too much or it might sound cheesy ... a little goes a long way! Oh, and it ONLY affects the microphones, not the background music.
4) The Bass and Treble controls control ONLY the music volume, not the microphones ... which is okay because the mics sound great, and that way you can crank the bass on your music track without messing up the mic sound :-)
5) The Bluetooth connects well, sounds good, and stays paired.
6) The battery lasts about 2-3 hours when using the system at FULL volume ... I imagine it lasts a lot longer when used at a lower volume.
7) I didn't use it to play media from a USB or Micro SD card, so I can't speak to that ... but I'm sure it works fine.
8) The included holder will hold anything from my phone to my 12.9" iPad pro.
9) My daughter LOVES the little disco light ... but I find it not so appropriate for my real concerts ;-)
She's already planning a Karaoke nigh for her class at school as soon as schools open. It will be sooooo easy to just use this with NOTHING extra!
Okay, that's about all. I plan to use this for outdoor concerts at retirement homes this fall, and I think it will be perfect. So simple and easy! Don't even need an AC outlet.