There weren't many reviews on this product when I bought it but the price was very affordable so decided to go for it. Hopefully this review will help others decide whether this product is for you. There is a basic version of this keyboard by midiplus that doesn't have many sounds (midiplus Easy Piano); I paid a little extra for the EK490+ to get more sounds. Glad I did because some of the sounds are quite good for an instrument at this price point.As an experienced keyboardist I didn't expect much from it, hoped it would be better than a toy. I wanted something battery powered I can busk with, easily move around on par with a guitar. This looked like it might be good for that. It has turned out to be pretty much everything I hoped for. Highlights are as follows:It has an acceptable key action. I would prefer a little more weight since I am a pianist but the positive tradeoff is less overall unit weight which is a real factor when carrying this device around. Light is good for mobile, which is what I got this for.In addition to an unremarkable but passable, slightly distorted piano sound, it has quite a lot of general midi type sounds (128) and some are quite good - electric piano, harpsechord, cello, english horn, clarinet, celesta, organ and some of the synth sounds are good enough for convincing solos. Some of the sounds are far better than I expected at this price point.It is easy to switch sounds if you know the instrument number you want.It is light and relatively small, yet the keys are full size.Battery power option means it has truly mobile capability and will put out sound without a power cord with 6 C batteries. It's not a huge sound but certainly enough for a small room or just to hear what you are doing without headphones.Octave up and down buttons allow you to easily switch to different registersIt appears to have the ability to record into memory and playback but I haven’t used that featureIt has midi in and midi out ports, but I haven't used them yet. I assume this keyboard should work fine as a controller.Overall plenty to work with as a mobile busking keyboard an par with an acoustic guitar.Idiosyncrasies I have discovered:Documentation is very limited so there are a few "tricks" I learned by experimentation:- If you plug in usb power there is no power to the internal speakers but headphone jack / audio out DOES work- the voice 1 / voice 2 buttons make a specific sound function slightly differently and on mine it seems the sustain switch for piano only works on voice 2 with piano sounds. Took me a while to figure that out.- On AC power the internal speakers put out sound - surprisingly weak on the default piano sounds yet quite good power on other sounds. Not sure why this is.- There is a separate "volume select" control for voice 1, voice 2, accompaniment. The default piano sounds seem weaker than the other sounds on the keyboard in default settings. It seems to help a little to turn up the piano sound with this "volume select" option. If you are wanting to push up the piano sound you have to do this setting every time you turn on the keyboard to over-ride the default setting. There are little lines that sort of visually show you how the "volume select" button can control voice 1, voice 2, accompaniment volume with the round knob. Expect to push buttons a bit before you get the hang of how this works.I wanted to have an option for long-term, rechargeable mobile power (without C batteries). So I hooked up a USB battery (big enough to charge a smart phone) to the USB port. This powers the keyboard for a long time without internal speakers operating or need for C batteries. I got a small rechargeable amp to put out a little more volume than the internal speakers do: Blackmore Pro Audio BJS 209 BT. This keyboard/amp combo puts out a pretty good sound for its size and totally mobile and "off grid"!Bottom line is I'm having fun with this little keyboard. Hopefully this review helps others decide.