When I was purchasing my first scooter I took my wife along for confirmation. I had narrowed my search to two second hand 200cc Aprilias - Sport City and Scarabeo. My wife looked at the large, comfortable seat on the beo and made the choice accordingly.
Yep, we do a fair bit of two up riding. Not long touring but day trips. I find that foot peg quality seems to vary quite a bit from puny metal twig like perches to larger, comfortable ones with rubber covers to stop one's foot slipping off.
On our way back from Stanthorpe, SharonVespaGirl and I met up with a "senior" couple who were touring on a Spyder. They had been on the road 2yrs and were still enjoying their explorations. The woman remarked how comfortable it was on the three wheeler. So yes, it would seem that two up comfort can be important in selecting a ride.