Jerm,
I'm running 6.1.0.4 (on an old 8500 with a g4/450 card and plenty of memory...). Ecstatic about the bang-for-the-buck, and general solidity, of Metro6
Between 6.1.0.3 and 6.1.0.4, the plug-ins display changed to the Apple plug-in tool. [1] I don't see any advantage over you old tool, and the Apple one takes more space on the screen; [2] and much more important to me....I use the "LowTech" coloring scheme, because the dark background (and resulting high-visibility text) is easier on my eyes during long sessions. But the Apple tool (currently) doesn't change to match the selected style...rather it LEAPS out from the rest of the display in its Aqua coloration. I hope that you fix this (or revert to the old display) by the time 6.1 reached non-beta release.
I have a few other comments, most of which I'll put in separate topics in the MIDI part of the forum.
Regards, --Lee