I upgraded from Grand Dink/Grand Vista 250 to Xciting 500.
Mostly because I found my wife, which is very happy cruising with me.
The pillion seat of the GD/GV is quite high, the pillion rider has a noisy ride with full wind blow. The Xciting has a more flat seat. But higher for the driver, small people shouldn't play with the Xciting.
And of course, the 250 lacks some power uphill with 2 heavy adults.
Another big difference is the much increased stability of the Xciting with his 15" front wheel in comparison to the 12" wheel of the GD/GV.
The GD/GV has its advantage with much more agility in city driving and his flat foot compartment where you could store some bulk.
I think the GD/GV 250 is an all purpose scooter, not too big (but already a little big) for the city and not to small (at least if you drive without pillion rider) for landscape cruising.
The Xciting is "only" a touring scooter. And that's why I have a small 125cc for the city too.
I don't vote because none is generally "better". They have different weaknesses and strengths.