Good and free M/S transient shaper. I like that you can chose between the mid and sides (or both) to be processed. That is a unique feature that other transient shaper I know doesn't offer.
Now some disadvantages:
The GUI is very small. Yes, this plugin was made a long while ago, but it really could have an overhaul to make it more suitable for modern desktops.
The "Link to Output Gain" feature is pretty useless. The gain compensation of the output does not work properly. Yes, it compensates a little, but the output is still significantly louder than the input. To cite the manual, "When engaged, the output gain is compensated depending of the transient amount to produce an almost unity gain." is not true.
The switch to change the signal to be processed (Mid, Side or both) works only via draging, not clicking. Very annoying if you want to use the plugin frequently for that feature, considering this one of the features, which makes BitterSweet outstanding from others.
Requires additional folder, in which the GUI png's lie. This also causes it to open up a little bit delayed.
Resume: After so many years, It really would deserve an update.