I commute on a 7200fx in NYC. It's only 8 mi round trip, but the 7200fx seems to do just fine.

My last bike was a Specialized Rockhopper, but I trashed it while mountain biking in Sacramento. Compared to the Rockhopper, the 7200fx feels like a much better commuter.

I find that I need to keep the tires inflated almost to the max to avoid feeling like I'm pedaling through molasses though. I'm very tempted to swap out to some narrower slicks, but I'm cheap, and the stock tires have plenty of tread left.

As far as add-ons, I've only added a bell with compass, front and rear lights, bottle cage, and Cateye Endurance 8 computer. I also flattened the gooseneck (?) so that the bars are flatter.

It feels a bit heavy to me, but I enjoy riding it. I've done a few 20 - 50 mi rides on it, and it has held up well.