Feature:
It could have more features, for sure. But everything it has works. Because of its portability, it is limited of course. If you want 5 octaves for example and need it badly and thinks it's annoying to use the switches to change the octaves, get a bigger keyboard, this is not for you.

Quality:
Very well built.

Value:
If you need more features, there are more expensive models. And the more the time passes by, the more common these things will be and they will eventually get much cheaper.

Desirability:
It's not the best model of controller in the market, but it's very very good. The XG sounds, the size, everything caught my attention. And the reliability of the brand too. Yamaha has been making keyboards since a long time, they know what they're doing.

Sound:
As some have not understood, this is not meant to be used as a performance keyboard. This is a portable MIDI controller, and this it's what it's meant for. Once you plug it in to your preferred audio interface, the sound is amazing. Those who know how to manipulate the XG sounds know what I mean. Sometimes it seems to have some glitches with certain softwares and MIDI, but not hard to fix. And as some said, the reverb is NOT on at full volume everytime. Mine never was, at least.

Ease of Use:
It's a bit hard to use it just with the knobs and sliders. But once it's connected to a computer, it works fine. Some functions are too complicated to be activated, like manual patch changes and octaves, but this is probably due to the small size of the product - it has to use odd key combinations to perform some tasks as it doesn't have specific keys for doing that job like changing patches or moving through octaves.

Support:
Not very good. I didn't have serious issues with it, but at least in the site there aren't many information or support or tips other than a download of the manual.

Overall:
I don't plan to replace it at all unless something as portable as this one and with better functions appears for a good price.

Overall:
Not glamorous, but a nice workhorse. I would never think of using it for performance, but as a small portable tool for working out ideas when you don't have a piano, or for portable midi entry into finale or a sequencer or something, I really like it. yeah, it's outdated. yeah it doesn't have USB, but the sounds are fine for what they are, and you get lots of them, and I love having built in speakers and the audio input. If you're working on Finale, it's great to have so you don't have to always go into "speedy entry" just to hear what you're playing.

Feature:
Along with extensive computer controllability, the keyboard features an audio input and battery power. The power consumption is such, though, that it's grossly underpowered with 6 AA cells. Battery life is atrociously short.

Quality:
The unit is well constructed.

Value:
The price-to-convenience-of-use ratio is astronomical.

Desirability:
But I'm stuck with it.

Sound:
Adaquate.

Ease of Use:
This keyboard is virtually unusable as a sole performance instrument, unless your satisfied with few or no patch changes.

Support:
Yamaha generally provides poor support for their products.

Overall:
I agree fully with the previous reviewer's comments. As a musician, I purchased this keyboard to arrange or transcribe music in a traveling situation in conjunction with a CD or MD player. The audio input is good for that purpose, but the short battery life makes it an expensive proposition, and external powering is extremely inconvenient.

Feature:
No 1/4 inch outputs, only RCA. Hands down the WORST user interface of ANY product in ANY category I've EVER encountered. There are only 3 buttons - up, down, and shift. To change patches, you have to hold the shift and press up or down. The glorious 3 digit LED display offers no clue of what sound you are on, so it helps if you can memorize the general MIDI patch table. If you try to audition a sound, be sure to lift up on the shift key, or else you will probably hear nothing, but you will transpose the whole keyboard a few semitones. And if you are too slow pressing the shift when changing patches, you will transpose the keyboard by a few octaves! The real kicker for me was in trying to turn off the reverb, which each patch is drowning in by default. Clearly this thing was meant to be used with a computer, but if I had a computer I'd rather have a soft synth and a USB controller any day of the week. This thing has a niche so small that you are probably not in it.

Quality:
looks fine

Value:
I was looking specifically for a module with mini keys and MIDI and built in sounds. Not too many choices there. Without that restriction, the Casio WK series is $100 less and several orders of magnitude more functional than this freaky thing.

Desirability:
This thing is like a sound card with three buttons and a keyboard on it. Nothing is as difficult to use as this, and I've used many many products.

Sound:
Sounds like typical yamaha XG synth, i.e. not too bad, except they are all soaked with reverb by default and it's next to impossible to turn off the reverb without using a computer. The internal speakers are extremely quiet and needless to say there's no bass whatsoever. They are essentially worthless, and they take up panel space that might have been used for more useful controls.

Support:
I returned it after I gave up trying to turn off the reverb

Overall:
I think I made my point by now. I'm buying a Casio WK3500AD for the same price.