Not only have I seen, heard and played one, I bought one. It arrived this morning. For a 28 lb. keyboard, it's built like a truck, very nice build quality. Long, box-end keys that feel great. This 76er feels better than the G70. Kurzweil pianos are excellent as are the strings and brass. Church organ is great, but the B3 sound is thin. It even has a few scat-type voices that are not bad. There's even a bank of pretty decent guitar sounds. And 64 drum rhythm loops - oooo! Navigation is simple, the only negative being the simplistic red LED display - way too old technology for this keyboard. At first glimpse I'd have to say that the Kurzweil SP2 is a keeper.
Before I put my e60 up for sale, I must admit that using this keyboard would force me to go back to my laptop and SC88 for SMF storage and playback, since the SP2 is not GM compatible.
Decisions, decisions. I now have three great keyboards, XK-1, SP2 and E60. Maybe I'll keep them all - for now.