Is a Xootr really worth so much money? I just checked because I like the idea and they're close to 300€ here.
I got the cheaper Dash model with the narrow plastic deck for US $200. If I were going longer distances (more than a mile/1.5km) then one of the more expensive wider-deck models would definitely be worth it.
If you're used to the cheapo Razor scooters, it's worlds apart, even from the larger-wheeled Razor A5.
The relative speed depends on the terrain. If you're on concrete sidewalks, like I am, I'd say it's 3x faster. If you're on asphalt, then 4x is reasonable. Downhill, 5x easily.