Node translation vs. Entity (field) translation
Randy Fay recently created a post discussing the possibilities achieved with of Entity Translations, where Gabor Hojtsy commented on some of the considerations to weigh:


  Some good things offered by [good old] node translation include support for separate node commenting (eg. your German and English comments will not be intermixed); support for per language revisions; publication workflows (eg. the German node can be in a pre-publication revision workflow while the English is already published, coordinated actions can publish multiple language versions when all reach a certain step in the workflow, etc); different permission handling (eg. certain people can only edit German translations not English originals), thanks to Drupal's excessive node access system, etc. Think about menus. Most sites do not plan to have 1-1 menu structures for all translated versions.


The major caveat as I see it for Content/Entity/field-level Translation right now boils down to that age old Drupalism special case: the node title... Its not really a field, so its not translatable without another module, and potentially some patch work.  As of right now, I think field translation is still very much "experimental" ground, but more power to you for pushing forward into new territory.