Based on your criteria its hard not to recommend staying with the Japanese brands. Availability, resale, parts, service options - its a pretty stacked deck in their favor. My ownership experience has been with SYM - Mio 50, Piaggio - MP3 400, Yamaha - TMAX, and Honda - Reflex & Silverwing (current ride).
In my experience, the Honda & Yamaha are far easier to own, have serviced/parts and resell. My Suzuki Burgman owner acquaintances seem to share the same viewpoint.
No diss is intended to any other brands, thats just my experience here in central MD. I just clocked my 7th year in scootering and hopefully have many more to go. Any future purchases will be either Japanese or possibly a BMW.
I don't do any wrenching or service work. I have a pro mechanic do house calls for service at about 35% of the cost of dealers and buy parts on the Internet. It was much easier to find a mechanic experienced with the Japanese brands than any other (to the extent thats useful, it very much is if you needed MP3 service).
Having babbled all that - my suggestion for your consideration is reaffirming your Reflex choice as a primo selection for your needs. They are a fine "mini-maxi", okay (but definitely not great, in high speed traffic) for slabs and very fine on secondary roads. Just my personal prejudice - if you go that route, take the time to track down one with ABS. Its a life saver.