Definitely "Leap of Faith"
"Godspell" was enjoyable only because of the vocal talent of the cast. When they weren't singing and acting out the parables, it was excruciatingly over-the-top. They used pop culture references at every turn and the attempt at comedy felt SO forced. However, the vocals were pitch-perfect so if you are a die-hard fan of the music, I would suggest seeing it.
"Leap of Faith" was surprisingly enjoyable. It wasn't perfect by any means. You need to suspend disbelief in order to engross yourself in the story, but the music is very enjoyable (much more so then Menken's "Sister Act), the cast is perfect, the plot doesn't drag, and Raul Esparza is a FORCE on that stage. When he preaches, you listen!
I would highly recommend "Leap of Faith" over "Godspell."
"I shall stay until the wind changes."