Twitter is a lot easier to post to than LJ. The Twitter app for Android is simplicity itself; one tap of the widget and I can type my message, hit another button to post and that's it. There is no official LiveJournal app for Android, the unofficial ones that exist aren't very good, so the only other option is the mobile website, which is slow and clumsy.
I also went through and deleted my past Twitter reposts. They were cluttering up my journal. I left posts that had replies, though.
I'll still be posting to Twitter, probably more often than LJ, I'm just not going to repost the tweets here anymore.