You don't need the midi but it totally expands your options. Hell, I run the soundiver on my crappy computer (think: Commodore 64 almost) and the tweaking is great. Plus being able to download zip libraries is really good for patches you might notta thought of. i found some "Beatles" patches that set me off in a whole new direction. Have fun! At $300 this thing is amazing. Just be warned that some dinos out there will rip on it, but F 'em. I like how it sounds with all my guitars and I have no wherewithall to own a fraction of these sounds out of vintage amps. I A/B'd some twin patches with my real '65 twin and like them as good--plus I don't have to hassle with mic and room bummers. Mind you, I never tried it live but the POD shines in a small recording situation.
This from a fella who talked with disdain about digital modeling and midi...I think the POD is a great value--even moreso if you can use its midi "deep editing" or whatever they call it.
Ree