I've been trying out synthetic reeds for years, but never been happy with how they sound or feel. Légère are not bad on a clarinet, but too "plasticky" on saxophones. Hartmann in general sound quite reedy, but I don't like the cut, the tip is too thin and they tend to be too bright. These Onyx ones, on the other hand, are perfect!
They're not like a perfect reed, but as good as a decent reed. Best thing is you can work on them, like a regular reed, so I just buy an H and shave it down. These clarinet ones don't really need any work.
Also, they last considerably longer than the Légère.