I have the PX4D (which, from glancing at the 5 on Musician's Friend, appears to be a lot different from the 5). Anyway, I think the 4 is useful for what it is--as I see it, basically a headphone amp to allow quiet practice. I don't think the preset tones are great; in fact I think many are completely unusable. That's the real downside for me--if they haven't been improved in the 5, I think you'll be disappointed. The metronome/rhythm feature is useful, which some nice options. Battery life is so-so. My TonePort/laptop combo, although not as portable, gives me a lot more options with more satisfying results. Good luck.