Don’t forget also that Ketron will be releasing the Audya later this year /early next year, and this looks like it could be something really special.
TIP, if you are used to using 76 notes (As the SD1 has) then do not pick a 61 note board, as you will regret it.
Other options are the Lionstracs Mediastation, (Providing you don’t mind doing a lot of work to set it up to your requirements) and the Wersi Ikarus. (This gives you a lot of the flexibility of the Mediastaion, but can be operated as easy as any arranger OOTB)
Please be aware that the last 2 are expensive in the short term, but cheap in the long term, as you do not need to change them again, but just update the software (And occasionally internal hardware) to give you a brand new instrument. (Software is considerably cheaper then swapping boards)
Finally don’t forget the Bohm Silverbird which is very comprehensive, and also hardware updatable.
As has been suggested don’t forget to try some converted styles first, as the SD1 is a mighty powerful board.
Enjoy whatever you play

Bill