I don't know if there is a distinction between the "comfort" model (no addition after the number) and the "sport" model (addition of fx, as in 7300 fx) for the bike you are looking at.
I used to have a 7100 fx, which I LOVED. Great parts for the $$. So when the 7100 was totalled in a run-in with a car (I was fine), I got the closest replacement I could find, which turned out to be the 7.2 fx. (I think they just moved from 7XXX to 7.X a couple of years ago.)
It's my commuting bike, I ride about 150 km on it, as much as 50 km a day, and it's fine. I wouldn't go more than that though, because I like to have other hand positions, and the bike doesn't fit me particularly well. But it's fine, really.