Why is progressive motorcycle insurance so cheap?

I got three quotes from three different insurence companies for a 2005 Honda 1100cc Sabre with under 2000 miles for 00, all three with the same type of coverage. The first quote I got from State farm they gave me a quote for 0 for the year, the second was Geico they gave me a quote for 2 for the year, the third was Progressive they quoted me with only 0 for the year with the same exact coverage as the other 2. I am 36 years old have been riding a motorcycle for about 2 years and I am buying this 2005 1100cc Sabre. Why is Progressive so much cheaper, has anybody else used Progressive and are they a good insurance company. It just sounds too good to be true.