Cufón vs. SIFr

This morning I replaced all of the SIFr-modified text on the site with Cufón, a JavaScript-only solution. Based on my subjective observation, Cufón feels like it’s a good three times faster than SIFr 3. I must admit I was a bit amazed – I had accepted SIFr’s slight lag in loading replacement text as normal; months back, I had tried a PHP-based solution that generated custom font images on the fly with a similar lag in speed. But Cufón was just short of instantaneous replacement, and it now makes the site’s headers visible on the iPhone or those rare desktop browsers that lack the Flash plugin.

However, there is a downside. Cufón-replaced text is not selectable and cannot be copied and pasted by the user; SIFr can, which is what drew me to that particular solution in the first place. But given the speed differences between the two, I’m willing to let go of that feature in exchange for a more seamless user experience. And if there is a situation where being able to select and copy text is important – such as using a custom font for whole paragraphs of text – I would certainly work with SIFr again.

That said, my brief experience with Cufón so far has made it seem a bit miraculous. Have you noticed any other disadvantages to Cufón? Are there other text-replacement systems I should be looking into?