Are there any Mezzo / Ori owners in the US, &\or Northern Califorinia? How available\easy are parts maintenance? What exactly is proprietary?

Am I really looking at $300-$700 to upgrade to nexus/alfine 8 or 11, when/if? Is the $300 too low, since I require parts and labor?
Is an I-4 really any smaller or lighter than Dahon Speed 7? I've seen conflicting information for i-4, 25.5 lbs vs 27 lbs for i-4, which is it (with fender rack)?
I-4's W13"xH25.2"xL29.53" W33cm H64cm L75cm doesn't seem smaller than 11.8" × 30.3" × 25.2" Dahon . I gues .8" can "make the difference" on occasion, baggage that will fit it? I'm clear Bromptons 9.8" x 21" x 22" in spite of more weight, wins this race. But I'm really not comfortable riding brompton or BF tikit (even when/if i could afford it) around my 'hoods thugs.
Is $500 "new", collecting dust at LBS, a good deal on I-4 (not sure what year)?

I'm kind of clear, if it was an option, I'd want Mezzo D9, Ori M9/M10, even a C8, before I'd want an I-4, but those aren't going to be available and I don't want to dismiss it out of hand.
I noticed some people who are taller prefer Mezzo - is 5'3" too short?

If it makes any difference, I'm 5'3", heavy, multimodal commuting, there are hills/grades in SF/Oak/Bay area (though I don't think the grades are major where I have to go, as opposed to where I might want to go). Does my area, or even just wanting to "get to work faster", mean I am likely to regret the I-4, pre -upgrade, sooner, than later over comparable more speed or greater gear range bikes? Or am I fairly safe, since at the moment, I won't really have experience of "better", so I don't know any better? Been a while since I rode a bike and I never really rode my mountain bike fast, unless I was coasting down a major grade.
I'm sure "test ride" is recommended, but that has its own challenges at the moment.