I reviewed key Kross/JunoDS differences in the post at
https://www.keyboardforums.com/thre...s-what-should-my-second-be.32202/#post-216965
The actions of the 61s are not worlds apart. They are both quite poor for piano, even as non-hammer actions go. They have poor dynamic control, and quickly become much more resistant as you move toward the back of the keys. You also mentioned the MX61, I would say that's the best of the three for piano sound and playability. What did you think of the action on your old Yamaha P413? I'm not familiar with that one, but I'd expect the MX61 to be similar if not better, so if you liked that better than the Kross action, that would also indicate you're likely to prefer the MX action over the Kross action as well.
As for sound cut-offs, you can assemble sets of 16 sounds on the MX where sounds will not cut off when you switch from one to the other (switching entirely seamlessly), but there will be cutoffs if you switch to a sound outside that set of 16. Other limitations to be aware of are, in that set of 16, only 4 can have insert effects; and you can only split/layer one set of the two within that set of 16 unless you use an external editor. In the end, every board has its pros and cons, it's just a matter of what's most important to you, and of course, just what you like the sound and feel of.
(As for the similar feature on the Juno DS, you can similarly assemble sets of 16 sounds with seamless switching, where 3 of the sounds can have insert effects, but you can also switch from ANY sound to any other sound without cut-offs, if you're okay with occasional glitches in the sound due to changing effects, more or less noticeable depending on the particular sounds you're switching between. NOt quite seamless, but still much better than having sounds drop out entirely, if you're trying to hold one sound or let it naturally decay while switching to start playing your next sound.)