My name is Dominic Russo from Buffalo, NY. I have played organ for almost 50 years. I currently have a Lowrey Stardust.
I am thinking of getting a digital piano. Have any of you made the switch from organ to digital piano?
To be fair Col, I think the main focus of his question is how easy is it to switch from unweighted waterfall style keys to weighted hammer action keys.
Plenty of people here have 61 key unweighted synths which play much like an organ.
Some like myself eventually evolved from unweighted synth keys to weighted hammer action synths along the way.
At first it takes a bit of getting used to the additional force to press the keys but the chords and notes aren't any different.
Playing style will also take a few skews from organ voices since the sustain and sostenudo pedals become much more useful with piano voices and the notes don't sustain the same as organ and synth voices do.
Then again, most modern electronic pianos include dozens if not hundreds or thousands of various orchestral and synth voices to explore as well as multiple piano sounds.
Personally I own quite a bit of keyboard gear as my signature explains, but in your case I'd suggest looking at a Roland Juno DS88 rather than a simple electronic piano if you want to have an instrument that will satisfy your needs for decades to come.
It has a very decent keyboard with hammer action and a decent touch that won't break your fingers when you're trying to play a fast arpeggio.
I should also point out that most hammer action keyboards offer anywhere from 3 or 4 to 7 levels of touch allowing adjustment to a weight that will most suit your personal style.