Gary, I also owned the Juno G...it was the worst Roland key feel I ever played, right there with the E-66....it was the main reason I sold it..
Believe me although the Prelude isn't much better...it is better...The keys feel a lot more resistant and I can live with the feel..I could not with the G..
Yes the JunoG, Juno Stage(not a bad semi weighted key bed), Prelude, GW8, and Sonic Cell...all use the Fantom sound engine..