Head over to Korg Forums.
Watch the Video Manual series
Watch the Webinars on Crowdcast.
I bet nine times out of ten of reviews that you have watched the reviewer is using a stock PA1000, as standard all Korgs are shipped with neutral audio settings, turn on the Eq and select one of the six available presets and the keyboard will become transformed.
The Sequencer is also superior to that in the SX, as is the OS overall where in line with current Korg logic features are unlocked and expanded as OS updates are released.
There is one USB socket for a memory stick and also a socket for a Micro SD card. I used a 64Gb memory stick and a 128Gb MicroSD card in my Pa.
There is a vast library of additional Korg sounds and styles that can be added for free as is Osimo which is a standalone Songbook that runs from the USB memory stick.
The PA is also a Sampler.
If you are used to the cr4p OS as used by Yamaha then you would be in for a steep learning curve but once learned everything becomes very quick and easy to do.
The heart of the Korg system is their Songbook, you save your chosen Style to Songbook as a specific Song, you then customise the song as you want and once saved a single press call up the Song to play. All this can be set to run from the a Direct folder on the USB memory stick which then becomes fully transportable to be used in other PA keyboards.
Sounds are customisable in Keyboard Sets.
One critical action that must be undertaken on all Korg Pa keyboards is the generation of a SaveAll file in addition to a Backup file for whenever the OS is updated the User data is wiped and the SaveAll file is then loaded and User Data is restored within the updated OS. Many owners have failed to do this in other words they fail to RTFM.
Don’t take my word for it that the Korg is imo superior to the Yamaha go into a store and play them back to back, the Yamaha does have very good piano sounds but the remainder are shrill and grating to my my ears. Just remember to go into the Global menu on the Korg and turn on the Eq.
I am not anti Yamaha, in that the SX is vastly better than the prior S models but you will still be up against the terrible support that Yamaha have, Saulo from Korg Support on the other hand is a star as are the Korg Staffer Guys on the various Facebook pages that are specific to the Pa.
I played a Pa700 v S775 and a 1000 v S900, Korgs were both better for my tastes
More recently I tried an SX 700 and SX 900 they are both very good and built better and sound better than the S models but the Korgs still have the edge.
I am pretty confident that you will not be disappointed once you have played both keyboards back to back.