You'll notice that a lot of titanium ring manufacturers say that they sell "comfort fit" rings. But what does that really mean?
"Comfort Fit" means that the edges and inside of the ring are rounded and smooth.
The ring is rounded to avoid any rough or sharp edges, since a titanium ring won't wear smooth over time. This makes the rings very comfortable to wear. Besides that, it just feels really cool when the whole ring is smooth. 
By the way: if the ring does NOT have a comfort fit, you don't want it! The "comfort" difference between a "comfort" fit and an "uncomfortable" fit is the difference between night and day. I have both types of rings. I only wear the ones with the comfort fit.
Most titanium rings have a comfort fit, but check just to make sure. All of the rings we recommend have a comfort fit.
The following example clearly shows the difference between a comfort fit ring, and a non-comfort fit ring. It is easy to tell that the ring on the left has a comfort fit, its edges are rounded and smooth. The ring on the right has straight edges, and is not rounded at all. Not quite as fun to wear.
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This is a GOOD ring. Nice, smooth and rounded on the inside edge.
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This is BAD. The straight inside edges are not rounded at all.
This ring would be like wearing a hacked-off piece of pipe all day.