I bought the NE 2 before the SV-1 came out if I remember it correctly. Anyway I have tried the SV-1 a few times and while it blows my NE out of the water when it comes to piano sounds, it just cannot compete on other areas. The organ SOUNDS good, but it is very inflexible. Both keys have nice leslie-emulations, though the Korg lacks the most important part, the drawbars. The korg does have nice keys for acoustic piano though those are much less flexible imo.
I personally find it a lesser inconvenience to play piano on waterfall keys such as the NE 2 has. However it is plain impossible to play an organ solo on the Korg. Of course this is something you get used to but still.
Finally, I find it surprising that no one has mentioned the clavinet. I use this instrument a lot and on the NE 2 it is extremely flexible and warm-sounding. The Korg, just like any other keyboard that even features clav at all, is nowhere near the Nord for this instrument. If you are looking for nice electric and acoustic pianos (except clavinet) then go for the Korg. If you want organ and clav, get the electro 2. If you want mellotron/strings/synth sounds as well, I would personally not recommend the NE 3 or Nord Stage, never liked those sounds too much. I'm looking at synths for pads/strings myself at the moment and not one single modern keyboard has impressed me so far... unfortunately.