I haven't actually done that, but from the hike we did from the top I could tell that you would get to see the most impressive stretch of the narrows doing the day hike from the bottom.

But if you can get a permit, and since you've never done it before, I would still say do the through hike (in one day or overnight), just so you get to see the whole thing. But that's just me. The hike from the bottom is also a very good option.