It really helps with the Kindle Touch and the Fire HD. I really don't need it with the iPad 3 though as it has good and sharp fonts. I'm still having issues with the embedded fonts showing correctly on the iPad 3 via KF8 docs, but I'll get it right eventually. They work really well on the Fire HD and so so on the Touch. Each device renders fonts differently so I need to research the best way to embed them so they work perfectly on all devices. Basically I create an ePub and convert it to KF8 with Kindle Previewer then send it to the Amazon Cloud.