As a long time LPX user I've been dabbling with using Harrison Mixbus (now at v4) for mixing and I have to say that in spite of the GUI looking/feeling a tad Windows 98-esque, the Mixbus mixing workflow (and especially the sound itself) is rapidly growing on me, enough to the point where I am not minding the clunky GUI. I do not (yet) see myself tracking with Mixbus or doing any deep editing with Mixbus, but the mixing workflow and sonic impact of Mixbus is understatedly awesome. Unfortunately it is not multi-touch friendly just yet but I've read elsewhere that that could be in the works as more and more people are requesting that from Harrison. Fingers crossed.
At any rate, I'd like to formally request that Mixbus be put on Slate's radar for a future Raven and Batch Commander update. I do realize that the more DAW's you support and make software for means more long-term maintenance and potentially more headaches down the road as each DAW evolves, however Mixbus seems like the perfect touch platform for Raven, especially as far as its mixing workflow goes. The more I use it the more I like it and it'd be nice to see the Raven and Mixbus play well together.