This keyboard pleasantly surprised me. I was a little reluctant buying it because of the incredibly low price, but the folding concept was interesting so I ordered one.I am comparing this to a Casio LK-S450 that I own. I did a ton of research (an embarrassing amount of research) and it wasn't easy. The important things to me were headphone capability, storage, mobility, small footprint on desktop or lap, key realism and playability and latest technology meaning usb-c connectivity, Bluetooth midi and built-in rechargeable battery. This keyboard checked all those boxes. Many of the popular brands don't check all of these boxes and they are unchanged for years. Built in Bluetooth is rare in portable keyboard unless you purchase an adapter for an additional $80 in most cases. This keyboard has built in Bluetooth! Comparing the keys with the Casio (that is over 3 times the price) , I felt these keys resembled real weighted piano keys more than the Casio because they were slightly "heavier" and I found them to be easier to control. Also when pressing the keys softly you get a sound where as on the Casio I sometimes got silence like it didn't trigger the sound. Are the keys noisy? I would say these would rate a 2 out of 3. The Casio is a 1 out of 3 (very quiet) and I have heard terribly noisy keys on other keyboards that I would rate 3 out of 3 for bad. The built in tones (piano, organ, etc) on this keyboard sound better with headphones than over the speakers. Volume is louder with headphones.Today, the latest connectivity is usb-c and that should be in all of today's devices. This keyboard has usb-c and it is used to charge the built-in battery and connect midi (wired) if your application doesn't support Bluetooth. The built-in Bluetooth midi and audio on this keyboard is great and is quickly recognized on PC and mobile devices and has worked perfectly for me. I found no signs of latency. I don't know what version of Bluetooth it is (4.2,5.0, 5.2, 5.3) that would be nice if the seller provided that information. The overall build is acceptable, not bad in any way just not to the level of expensive units.It's not noticeable while playing. The hinges are metal and securely fastened, however I did notice a bit of play in the metal hinges. This too is not noticeable when on a desktop or table but is when on your lap. I would like to see the gap at the fold to be tighter when locked open for use. The idea of folding the keyboard is fantastic. There is a ribbon that delivers electrical to both sides of the keyboard and that ribbon cable looks very high quality and durable. I can't see it being a problem if it's not abused. When folded, this keyboard is so compact (19" x 9" x 5.5") and fits nicely in the included carry case and that can be placed in a carry-on or backpack. It comes with a pedal and a high quality sheet of stickers (musical notes) that help beginners learn and recognize the notes on each key. They stick well and easily peel off when you no longer need them. Overall, I'm extremely happy with this keyboard for my needs. A great beginner option with lighted keys and everything you need to connect to your favorite online music app and start playing.