Ken,
You are doing the right thing. Ride as many bikes as you can and find that one that fits you and that you feel good on. A better bike now will pay off in the long run. If you look over some of the Clyde's histories, you will see that most start feeling the need for more speed as their weight comes off. So, you may see the need for a road bike at some point here too.
The Giant's are very good bikes. Right up there with the Treks and the Specialized bike to be sure.
Good Luck to you!
Chris