The guitar version on Zoo TV is simply awesome, even without Bono and his drugs on the B-Stage... "Running" sounds awesome in each ZOO performance, specially in late ones (late Zooropa, Zoomerang and Zoo Japan), while the piano f*cks up the song in each piano version...
On the other hand, the great snippets which can be put into Running (Dirty Old Town, <<I'm still running..>>, Amazing Grace...) cannot be put into the Guitar version.
Each version has it's good and it's bad... But I prefer guitar
Piano version is very good (like Rattle and Hum and Point Depot shows ) but i like more the electric, the shimmering sound and the awesome transition with Streets