I like this keyboard
Overall this is a great keyboard. The finish looks decent, the buttons have quality feeling both when looking at and when touching. This is my second keyboard which I pre-ordered before its release and already own it for more than 4 months at the time of writing this review. I have never had a fully professional keyboard though. My first keyboard was Yamaha PSR530 which had been just released when I bought it in mid 90s and which was a decent mid-range keyboard at that time. Well, it is obvious that technological advancement brought the keyboards nowadays to a new level compared with ones a decade or more ago. So let me list what I liked in this keyboard so far, and what I didn't like that much.
* Not a narrow list of accompaniment built-in styles. I have been quite OK with built-in 181 styles. I'm pretty much sure almost all of them are of high quality. Though I've not tried playing with all of them yet.
* Voice quality is between good and excellent. Well, most sounds are really realistic (but not all, see Cons), especially guitar sounds.
* Expandable. This is a cool feature. I've already bought and installed the oriental expansion pack which gave new voices and styles to the keyboard. With this feature you are kind of peaceful that your new keyboard will not get outdated too soon - you can give it new sounds and styles whenever you want (well, there is a storage limitation, see Cons).
* The external look and layout overall feels kind of minimalistic. Which I'm not so sure whether is a good feature or not. But I like it. Looks quite professional.
* Good quality of speakers. No distortion at all even when the volume is fully maximized.
* Has a flash disc USB port. You can use this port to install new expansion packs. To install new styles. To export your recorded songs. Like it very much.
* Lightweight. Yes this keyboard is quite lightweight. Even you can hold it on your single finger easily. Well I can and I'm not a very strong guy physically. :) This was a joke, but it is really lightweight.
* Only 1 audio out port. Even my PSR530 had two of them. One would not block (mute) the sound from the speakers which would be quite handy when you want to record a song playback from your keyboard to your computer. But with this 1 out port, your speakers will be muted so you cannot listen to what is being played during the recording. Well this can be overcome by a pair of headphones plugged into the computer, but still not so comfortable.
* Screen interface is not very user friendly. Because the keyboard has not too many buttons (which as said above look quite cool), the screen has a kind of overloaded functionality. I already used to use it flexibly, but still not as flexible as I would do with my previous PSR530.
* Some violin sounds are not so good. Especially solo violin voices sound somewhat artificial, somewhat cheap. Even the new Sweet Violin voice is not that good. Not the same or close to e.g. guitar sounds which are really great.
* After recording songs you cannot change the instruments on different tracks. At least I cannot find a way to do it. It's possible to change individual track volume, pan, etc, but not the instrument the track is playing with. This is kind of limitation, but not a serious problem though.
Overall, I'm pleased with this keyboard. This is not a toy, but a serious keyboard. I believe I will use it for a long time and that it's a good value. If I would to give a "yes" or "no" answer to this keyboard, I'd definitely say "yes". I recommend Yamaha PSR-S650 as a mid-range keyboard suitable from hobbyists to professional musicians.