I like the fact that using Metamorphic Transfer with an Outsider that has the metamorphosis power and a minimal manifester level allows you to use 9th level spells as supernatural abilities (look at the nightmare for example) up to 3 times per day.
And that one use for that is by casting astral projection, which not only gives you effectively an extra life, but it also gives you extra copies of all of your magical stuff, including consumables (and that consuming them apparently leaves the originals fully intact).