Extremely useful tool. It is everywhere in my projects now - on single tracks, group tracks and the mix-/masterbus. There is nothing like it out there - the absolute best stereo widening and mono tool, and I love the monitoring options. The whole GUI is so well constructed (just like bx_limiter, the XL knob is pure genius). An absolutely essential tool.
This plugin has been the first in my mastering chain for years now. I use it for final gain adjustment of the mix, for creating a mono signal below 90Hz, to adjust the width of the signal, etc. I could not work without it.
Good M-S toolbox
The bx_control has every option and, well control, over M-S stereo you could possibly wish for - both for decoding and encoding. The included metering part is not good in my way of working though, as the dynamic range reported is much lower (roughly 4 dB) than what I'm used to from the old TT-meter and other software. It's not a bug as the bx_meter shows the same, it's a different measurement and/or algorithm. Outside of this, it's a great tool!