I'm looking to get into mountain biking but want a bike I can ride to school (3 miles one way) too. I'm looking to stay under $400. I went to a shop and test rode a Kona Fire Mountain and a Scott Voltage YZ 4.

I was really impressed with the Kona, although I don't know a whole lot about bikes.
The chain came off the Scott on the first attempt to ride it. It rode good though on the second try.

The guy said I good get the Kona for $385 which seems like a good price (plus free servicing and 10% off accessories for a year).
The Scott was $315 with the same deal.

I'm going to check out some other shops, but is the Kona Fire Mountain a good bike for a beginner and is that a good price?