I guess it really matters what feels and sounds good to you.
The Krome EX has the great piano sounds (although I did not like them much) and EP sounds (which are great). It lacks some of the features that the Kross 2 has, but the Krome does have the piano-roll sequencer AND the touch screen. The keybed on the 88-key is pretty much the same as the Kross 88 keybed. I believe they are identical.
The Kross 2 is a formidable instrument and has come a long way since the Kross 1 (which I have 4 of). I find them very useful and versatile. You also have the ability to record audio on the Kross units, and it has sample pads. The sounds are good, but since there is only around 150Mb of samples, it is much less than the Krome in that regard. What Korg have done with the EDS-i in the Kross is quite good though.
Some people talk about the keybeds on the Kross, but I guess they do not bother me much. I have two of the Kross 1-88 and two of the Kross 1-61. Both are fine for me and I do like the weighted action, even though it is not really close to a real grand piano action.
Some also do not like the LCD screen on the Kross, but there is an editor, both standalone (for PC) and a plugin (for your DAW) and it makes the Kross MUCH easier to program. Korg have also released some soundpacks for the Kross, but I believe that the newest iteration of the Kross 2 has them installed already.
Maybe they could have done more with adding more sounds, but there are soundpacks all over the Interwebs that emulate different sounds that other bands used.
My last foray into Roland synths was the XP60 and I believe that the Juno DS and FA series are pretty good, although they are much different than products before and are much different than anything Korg has.
With regard to Kurzweil, I really like them too and the PC4 could be a great option. My experience with Kurzweil is a bit negative right now because I have the SP1 and the runaround I got from Kurzy on it left me dismayed, at best. With that said, the SP1 is a digital piano and I have got it to where it will be the main controller in my live rig and I LOVE the action on it. Maybe their more costly offerings are better positioned than the SP1 is.
With regard to the type of music you are playing, I see a lot of people using Korg products for Symphonic Metal, Progressive Metal, and so on. Bands like Nightwish, Stratovarius, and many others seem to use Korg for their orchestral sounds. Jordan Rudess from Dream theater has been a long-time user of Korg products, but I remember him using Kurzweil products back in the day as well...
I would takea listen to them, watch the videos, and get a feel for what zings you. From that point, go play some of them and see which really speak to you then. That really is the only way to decide on which one you really want.
I wish you luck, sir
Grace,
Harry