Yes, we had a team that spent some hands-on time with LogPlex for several weeks. It's obviously a very capable project used at scale for Heroku and successfully implemented there.
Ultimately we have decided that while the goals are aligned, the team was not able to be very productive with LogPlex. Some of which was due to lack of Erlang familiarity on the team. Some of it was due to difficulty understand it from the at-the-time documentation and test coverage (which I think may have improved some since the first effort started). Some of it was due to perception that it was closely tied to some of Heroku's architecture, which was not as adaptable for our needs. Whether others feel those are accurate or not, these were our realized experiences after digging in on it, hence where we are now.