My only problem w/ Dissipation is that you have to resummon fairy. Swiftcast + Summon uses a GCD that would be better spent healing. Sometimes this isn't a problem though. I use Dissipation near the end of fights so I don't need to resummon.

btw, I forgot that Rouse exists. Rouse should be on CD when you use Dissipation, so you don't lose extra healing.