I have the Mercier Galaxy AL that I bought from bikesdirect.com and have been nothing but happy with it. I have over 1,200 miles on it and it is a fast bike and well worth the money they sell it for. I am not saying it is a great bike with outstanding components or anything like that. I am just saying that for the money, this bike is as good as anything your local bike shop will sell at double the $450 price.
I have been riding this for the past 3 months with a local bike club that has over 100 members and ride in the upper B group. I do not feel handicapped at all riding this bike against $3000+ bikes and think it was a smart decision to buy it and see if I was going to continue riding before moving up to a more advanced bike with lighter weight and better components.
The Mercier Galaxy AL rides and handles very nice, shifts perfectly and is comfortable on 40+ mile rides. The weak link for me is the brakes, they are adequate but barely. As with any bike, proper set up and fit is the key to expected performance. Then you have to have real expectations too. It would be unfair to buy a $450 bike and expect it to perform like a $4,000 one, but in this case.... the gap is not that huge. I am sure that this bike will meet your expectations and there is no sense in spending a lot of money on a bike unless you are determined to put the bike to good use.
This bike will help you find out if cycling is the right sport for you and take you pretty far before you need anything better.