Here's an easy to understand explanation of the differences between the two models. Hopefully, it will help you decide.

https://www.bonnersmusic.co.uk/yamaha-psr-sx700-vs-psr-sx900.irs

Very helpful Mike

Thanks very much for that Mike, big difference I can see.

And this has also confirmed the question I've been asking for a while:

Thanks Mike. Definitely gives the nod toward the 900!

You're all very welcome! Glad it helps.

Mike, there have been so many negatives, but your post put me right back on track.

Thanks, John C.

Thanks Mike! Definitely a good find!

is there a SX900 vs Genos chart somewhere to compare also?

So what is realistic price we can expect to pay in US for each (700/900)?

Yes, and while you're at it ... find a comparison between a Rolls Royce, and a Lincoln.

$1499.99 - $2199.99

What styles and voices are “missing” in sx700 from sx900 ?

Thank you so much.
I went with Psr-sx900.

Congratulations Vadim,
Enjoy your new keyboard.

Thanks for the link Mike

For me, a big difference is (quote from Bonner's)

The PSR-SX900 has a 50w sound system (15w + 10w x 2) for a MASSIVE SOUND! The PSR-SX700's sound system is total 30watts (15w x 2). The PSR-SX900 speaker configuration is slightly different with the use of dome speakers for a fuller, enhanced sound.