I started with an entry level Giant Hybrid and it met my needs for a while, but when I took to riding regularly with groups, I was on a heavier bike with fatter tires than everybody else; I had to work a lot harder (and it was like driving a truck amongst sports cars -- accelerations and decelerations required constant attention).
If you're mostly going to be riding on your own, or with some people chatting as opposed to a paceline, you'll probably be happy with the 7300 - though you might want to move to thinner tires at some point if you're on the road.
I went to a 7500FX (now a 7.5, I thnk) when I wanted something lighter and I love it -- the bar isn't that much higher, and it is great for riding reasonably long & hard. However, it's aluminum, so if it's a week of 50+ miles a day, that beats up my butt so I go back to the original hybrid and just work harder
When my friend was in a similar situation and was looking at the 7.3, I convinced her to give the 7.5 a spin around the parking lot. She liked it a lot better and got it.
So... bottom line is, what feels good to **you**. Which one do you feel like you could just keep pedaling? THat's what led me to get my first bike, and I still put 5-6000 miles on it every year.