Ian, I haven't played any other Roland with the same action yet. Admittedly, I haven't seen a Jupiter yet, but I've played some of the Juno's...not even close!
I wasn't all that impressed with the BK3 and BK-5 actions. Admittedly, they still felt better than a PSR, but nothing like the BK-9. That is crisp, precise, and quite a pleasure to play.
I was even more interested in trying it for myself when my friend who bought the Tyros5-76 said he tried a BK-9 at a music store out West and he was a bit concerned that it wouldn't stand up to his playing over the long haul, plus, he said it was actually too light (go figure that one) and it wasn't easy to secure on the stand it was on(the kind with 4-legs...a K&M).
He also mentioned the data wheel as feeling a tad fragile.
Otherwise, he said it sounded great, and he thought the acoustic pianos were very well done, and the Rhodes sims were especially nice and expressive.
In any case, Johnny grew up on acoustic pianos, and plays pretty hard, and most synth type keyboards don't usually last long under his big fingers...his 9000 Pro has
only had to have the strips replaced twice over the many years he's owned it, and hopefully the Tyros5-76 will stand up even better. He really likes the action so far.
PSR instruments were never a consideration, as you will understand.

His concerns were what piqued my interest even more in trying the BK-9. I'm sure I'll like it, as I'm not that heavy a player, having spent so much time on Hammond AND weighted actioned pianos, so I'm able to adjust to something lighter...e.g...I have no problem on PSR's.

I also want to be able to personally recommend the BK-9 to those wanting a 76'er that is much less expensive and more portable than a Tyros5-76, which is a bit on the large side, although, I must say, it does look very impressive, especially on the L7S stand, which was made for it.
It is a big chunk of change nevertheless.

I've checked with Roland Canada regarding similar keybeds to see if they can tell me what other 'boards use the same keybed...I was thinking it was the Jupiter-50, but I want to be sure. No word yet.
Maybe I can talk them into sending a BK-9 in locally...worth a try.
DonM seems very pleased with his, and I trust his judgement as I do yours and Fran's (I'm looking forward to Mr. Carango's impressions).
Ian