Plastic reeds (Legere in this case) seemed worth trying, stable, no adjustment, impervious to changes in temperature etc. I really wanted them to work.

I tried a variety of strengths and models on my usual mouthpiece and others that I had on hand.

My conclusions are basically; if you sound better using a plastic reed then you know little or nothing about reeds. You might get from a to b right away but kiss any hope of seeing c goodbye. Anyone with an ear will be able to tell the difference. You are going to seriously limit your expressive capabilities.

 If you are too lazy to spend 10 minutes and a little money on making a cane reed work then you probably don’t have what it takes to be a good musician.

There are possibly some cases where you could justify using one but you will still get better results from a cane reed.
Mouthpiece curve and tip opening must match the reed profile. Assuming the mouthpiece is symmetrical. This means basically only one curve matches’ reed the reed exactly for the sound you are trying to produce.
The profile of the reed has to match the facing of the mouthpiece to some degree, this can vary to make different sounds but beyond certain parameters it won’t work.
It is possible to find a combination of plastic reed and mouthpiece that match given the particular sound you want to produce. This however is unlikely.
The more discerning you are as a player, the less likely this is to be.

Means of adjusting setup removed.
No musician of taste and sensitivity is going to want to make the same tone for every piece, composer ensemble or hall.
One of the ways of changing the tone to suit the artistic requirements of the performance is in the selection of the reed.

 Play test -plastic reed detected 10/10 times
Other than playing single notes very softly mid range (where basically all things being equal everyone sounds the same) my colleagues were able to identify the plastic reed every time and described the sounds as thinner, less warm not as nice, inferior less preferable for the excerpt etc. This was the clincher for me; I want to sound good, why would I do something to make myself sound worse.
If you have a plastic sounding tone to start with you probably won’t notice the difference.

Happy accidents and Bertrand Russell [This is the important part]
If you remove a variable from your playing, you limit your possibilities. You achieve more stability, but at a price.
Occasionally a reed will surprise us by the sound it produces. Bertrand Russell said that all things we can conceive of must necessarily be composed of things we already know. If we only know the non-changing sound of our plastic reeds we are doomed to live in a sterile and uniform world

A cane reed is an organic and unpredictable thing it can make sounds that surprise us, awe, disgust or move us. With cane reeds the sound we can conceive of can mimic or contain properties of all these different sounds, extending our expressive capabilities.

So, when could you justify using one? Well I never do (Ok I have one in my clarinet case, but only in case I forget my reed case at home)

 but one could perhaps use one for ·
Outdoor concert or loud band type concert where your tone will not be obvious
· Poor playing conditions where cane reeds might dry out, like a pit for your doubling instrument (though I have played lots of shows, even tripling without having cane reed problems)
· For a beginner so they don’t have to worry about the reed not working (I don’t do this) · Playing for students in lessons so you don’t have to demonstrate on a dry reed
· To warm up on while your cane reeds are soaking.
 
Lastly playing music is a basic human activity or desire from which we derive satisfaction, but so is the making of instruments. Working on reeds adds a degree of participation, which increases the quality of the player’s experience.