The is a attempt of comparison between.
Both have there advantages and there contras

The Juno has a excellent filter resonance, it has real pulse width modulation, a fast LFO and a second chorus.
But is not very flexible, only one DCO.

on the other Hand

The 3P have 2 DCO which can be tune separately with LFO and Envelope modulation, faster Envelop, a sync and ring-modulation mode and a serial midi interface.
But the Filter Resonance is not as good as in the Juno and it has no real pulse width modulation.

I think both are great synthesizer :-)
Which is your favorite ?