note for those that haven't dealt with mid/side matrix plugins, hardware (or have done m/s recording for that matter) this is one way to eff up your track by not knowing what your doing, hell, even when you do, as most mastering engineers will tell you. it's meant for fixing finished tracks where the stereo field needs some work, defining the mono (bass/kick/vox/etc) and widening/shortening the stereo and much more.
a few other's that offer m/s are
apeq,
neon hr, the eq in both
ozone 4 and
tracks3,
fluz epure and soon to be
ddmf lp10 (pay what you want price and wicked set of eq's, check it out if you haven't got it) one thing they all have in common is that they're meant for mastering first, though can be used anywhere, i'm not sure about ozones eq but the rest are linear phase (can't remember if brainworx digital and hybrid are too). there a more m/s matrix compressors/limiters, like
fabfilter pro c taking shit even higher in specialist tools