At 235 lbs, I'm a big enough fatty that the difference between 2 up suspension and my own is negligible. The bike still handles wonderfully with my girlfriend on the back: plenty of power, and fun in the turns. Getting back-humped certainly is an interesting experience though. I guess it's more comfy for me given that I ride an xb12ss instead of one of the shorter models.
No gear, no ride is the way I work too. Girlfriend has an expensive helmet, expensive jacket, expensive gloves, and good pair of heavy duty pants and boots. I would rather spend the money to make sure she's safe than give her some bargain-rate gear that will eventually lead to her injury.