My girlfriend is 5'4", and when she took my Vespa ET2 50cc for a drive, she had trouble getting it on and off its center stand. Of course she was wearing flip-flops at the time...
So when it came time to get a California scooter, living in SF, the Buddy 170i seemed like the perfect choice. It's significantly lighter/smaller/lower than the Vespa. And in addition to the center stand, it has a kickstand...so if the center stand is too hard... Oh, and it is ZIPPY as heck. And very easy to drive. And cute. And lots of storage. And by all reports, reliable and cheap to fix. (So far, it's running awesome.)
We still don't know what it's like for her to drive, because we're still waiting for her to get her M license (necessary for 170cc in California, unnecessary for 49cc in Massachusetts).
I am 5'10" male. Average size, except for my feet, which are size 13...which is actually relevant, because my feet literally do not fit flat on the floorboard of the Buddy. Either I have to hang my toes out, or I have to slope them up towards the glovebox. At first, this bothered me, but I've gotten used to it.
Have taken it in the twisties a bit. The tiny wheels make for awesome low-speed maneuvering, good mid-speed stability, and somewhat nervous higher speed (above 50mph). It doesn't settle in at high speeds the way my Ninja 500 does (duh). Something (center stand?) scrapes at relatively mild lean angles to the left. Of course, I do get some secret satisfaction out of scraping something in a turn.

. Even scraped riding two-up.
We have ridden it two-up (me + girlfriend + laptops, handbags, etc. under seat and in top case) commuting over the Golden Gate Bridge, up to 60mph or so (actual), occasionally at night, occasionally in the rain, occasionally with high winds. I can't exactly recommend any of this. While I was never in fear for my life, I believe she might have been. Going more than 5 or 10 minutes on the highway is not ideal, from a comfort point of view...and having more than about 200 lbs. of human + cargo limits your ability to hold highway speeds up hills. And your only way out of trouble on the highway is to slow down...speeding is not a real option. And riding two-up, there isn't quite enough room for everyone's feet/hips/heads. The Vespa ET is noticeably bigger and more comfortable in this regard. Buddy's suspension does not seem to be set up for two-up on bad roads.
For Bay Area people: Golden Gate Bridge, from Sausalito into the city, is okay, and other quick jaunts on flat parts of 101 are okay; Bay Bridge is suboptimal, I80 and connectors are not fun, and I have no intention of trying 280.
Having said all of this...I love LOVE driving the Buddy. It is perfect for zipping around Marin and/or San Francisco. It's faster than most of the cars out there...partly because it's so tempting to crank it at full throttle, and most car drivers don't make a habit of full throttle takeoffs. For cutting up traffic, up to 50mph or something, it's pretty hard to imagine a better tool. Definitely fast enough to have some fun. I can imagine having similar fun with it in Boston, NYC, London, Paris...surface streets in almost any city or country roads (not interstates, M-roads, autoroutes, whatever you want to call them). The front end gets light when I nail it...I'm thinking wheelies might not be out of the question...and the brakes do everything that's asked of them, even on hilly SF streets with 300+ pounds of people and stuff on board.
Parking it is about as easy as it gets.
Cumulative MPG: 67.5 (including lots of full throttle work).
Starts the first time, every time.
Would I buy it again? For girlfriend, for city use, without a doubt. If I had known we would be commuting across the Golden Gate Bridge, maybe. Or maybe something more powerful. A small 500cc scooter like a Kymco or Aprilia has an obvious appeal...
I have a 500cc motorcycle for myself now. On the highway, the motorcycle is altogether more confidence-inspiring; in the city, I definitely prefer the Buddy; and on low- to mid-speed back roads, with or without a passenger, I have to say, the Buddy really is more fun (and less demanding).
Hope this post is helpful to someone!