Please explain the use of Compresser. Is this software used for BluRay burning or is Toast better?
Roxio's Toast is something different, although both apps have some overlapping areas, but lil'.
hard to compare both (comparing apples and oranges … )
if creating disks with individual menus is your main purpose, Toast is 'better'.
but there are better authoring tools than Toast, Adobe's Encore for example.
for Roxio Toast? afaik, yes.
from within FCPX? afaik no, but … you'd need an additional, external BR-burner.
or, for projects <20min, you burn a BR-structure onto a DVD-r (aka 'mini BluRay' or 'AVCHD-disk') .... not compatible with any BR-player.
"BluRay is a bag of hurt!" S.Jobs
== edit ==
oops - wrong board, you're using iMovie? thought I'm at FCPX-board ... sorry!!!