Personally I think the Defense Saddle holds more value than the Comfortable Saddle.

I say this because more times than not, when you auto walk, you're running into random mobs faster than the saddle would be able to do much healing. Sometimes it can't heal you before the next battle given certain cases.

Defense Saddle Adds +20% of pet's Defense to yours so if your pet has 200 Defense you will get +40 Defense.