Pros: cheap, fast
Cons: cheaply made, poor warranty service
I've never owned or even seen an X-Treme scooter, but in the process of researching electric mopeds prior to purchasing one, I read a lot of really bad reviews of the X-Treme line of products.
Basically they're appealing because they're cheap, but they're cheap for a reason. They tend to break fairly easily, and service and maintenance are very difficult to obtain. I believe the mopeds come with a warranty, but the manufacturer tends not to honor the warranty.
From what I've read about X-Treme, you're better off paying a bit more for an electric moped from a reliable manufacturer like ZAP or Skeuter.