Does schematic sound good?
No. You have to build the circuit!!!
It's a fairly standard "diodes to ground" clipper effect, which tries to "soften" the onset of clipping by the use of MOSFETs instead of simple diodes. This does have some marginal sonic benefits, but you're probably unlikely to hear much difference unless you're very careful with the way you play so that the level of the instrument fits perfectly to just the curved part of the MOSFET characteristic.
The tone switch has a very marginal effect, and this kind of effect really needs a much more effective tone control to be musically useful. The values chosen in the circuit give a fairly useful over all frequency response for guitar, but it's really not at all special (and doesn't really warrant the huge number of posts discussing it!)
As an experiment, in a recording studio recently, I had a box with me that allowed switching between different types of clipper. The basic circuit was a low noise Tubescreamer type (circuit in another post elsewhere here on this forum), with the option of differing diodes, MOSFETs, transistors and LEDs for clipping. The clippers could either be connected to the inverting input of the first op-amp or to the mid-rail (which is AC ground because of the large electrolytic from the midpoint of the bias potential divider).
I had several musicians and engineers "audition" the effect, and we did "blind" testing of the different means of clipping. In each case, the levels were carefully adjusted to remain the same, so that "loudness" wouldn't be a factor in their comments about the sounds. We found that there were three discernible types of clipping, and all the rest sounded much the same as one of these three:
Diodes in the feedback loop of the op-amp (like a basic Tubescreamer)
Diodes to ground after the op-amp
Asymmetrical diodes in the feedback loop (very marginal difference to the first).
It didn't really matter what kind of clipper you used!!!! In most cases the only differences are the point at which distortion starts - germanium diodes clip at 0V2 p-p so will seem more "sensitive" than silicon one which clip at 0V65 p-p. LEDs are even less "sensitive" because the take even higher voltage to conduct. There was a slight difference audible with asymmetrical clipping (though, on average, only three out of ten listeners could hear the difference!).
After the experiments, I was really quite disappointed - I felt sure that there would be a noticeable difference in sound between differing types of clippers (not just the point at which clipping starts, which is what I found). The most important part of the over all sound of the effect is the frequency response before and after the clipper stage (a low pass filter before the clipper makes your effect really smooth), and the best we can really do is to put a really effective tone control circuit after the clippers. We also need to keep the noise down!
I plan to repeat the experiment with a set of "Fuzz Faces" and "Tonebenders", and see how much variation people find.