It's ok (lower case). You can feel it, you can hear it, the drag is more than my dyno hub, less than the old bottle generator I had on my Wester Flyer. I keep it on my beach cruiser, which actually gets used at the beach.

Here's the trick, lube the hell out of your chain, pour lube in the case before you install it, and then after you put it on pour more lube in the small fill hole.

It does a very good job at keeping your chain clean. If you live on a dirt road, use your bike on the beach, or live in snow country, it is advantageous to have.

I like it on my beach cruiser, and since I live on a dirt road like it around here.