I fall into the pro hub-generator camp, but mainly because I get a kick out of using the bike to power my electronic devices. I've toured coast to coast, taking lots of photos and blogging daily on an iPad, without ever plugging in. (I charged a cache battery during the day that I used to charge whatever needed it at night.)

But, I did this for the novelty... I would have had more than enough opportunities to charge the battery from wall outlets while shopping, eating, etc. That said, I really did enjoy it.

And, some days I do enjoy starting before sunrise, and I like the reliability of a generator for this. I know it's not hard to just carry spare batteries and change as necessary, but I prefer the convenience of the generator.

As others have said, the value of a generator on a commuter is more clear, but I'd say just go for it if you're tempted. Why not?