Since, according to the ebuilds currently in Portage, Logjam seems to have never been marked stable on PPC, I thought I should report in! I have been using it, lightly, for the past year, and it works just fine. I've used most of its features, such as spell-checking, journal updates, recalling previous entries, friends lists; no problems noted. I've used versions 4.4.x through 4.5.2, all without problems.
Sure, I've marked logjam-4.4.1 stable on ppc. Thanks for the report! If there are any other packages that you use that aren't marked stable, please let us know. :)