It probably has lead acid batteries which are pants. They fail if you ever leave them discharged for a few hours. Also, they hold little power for their weight.
If you want an electric bike be certain that you should be going for something with Lithium Polymer batteries. They aren't cheap but are better in the long run. Failing that I would go for nicads, because though storing less power for weight than NIMH, they have a longer life by a factor of about ten in charge discharge cycles.
Best thing is to take a look around the Electric Bike sub forum on this site. It is full of back biting, but there is some good advice there. They probably even cover this model you cited.