I was concerned about the "weight limit" when I bought my i167 (used), but I haven't had any problems at all. I'm 6'6", and weigh in at about 300 lbs.
My first ride was on a friends' machine (thanks, Steve - look what you started
), and I only had the "shakes" for a minute or so - until I realized that I didn't have to do anything about balancing (pretty much like everyone else, I expect). Since I've gotten my own, I've progressed to the Red key, and the only thing I notice is that the battery may not last long enough - I solved that by upgrading the software at Jaredfest, and getting a set of Li Ion batteries.
Last week, my wife Pat and I went to the big Springfield OH Antique show with our Segways (she has an i170), and ran around (slowly) for 7 hours without running out of anything except personal energy
(hey - even on comfort mats it takes something out of you to stand up for 7 hours).
We had a great time - even drove the Segs through the narrow aisles in the buildings. I went into any booth the had a wide enough opening for the wheels to get through. The only problem we experienced all day was a careless
walker who tied to walk right through me from the right rear, and I managed to avoid her without damage (it's hard for me to believe she couldn't see something as large as me).
What slowed us down the most was all the people that just
had to talk to us about the Segways! Only 2 of them were silly enough to ask about doing wheelies (I told the 2nd guy I was on a perpetual wheelie
).
And now my 5'5" wife knows what it's like to look down on peoples heads like I always do
.