If I'm really honest I can't tell the difference between them, I'm not sure that it was worth the effort... some feedback would be most welcome 
The non-linearity will produce a wave shaping effect. I'm guessing it'll might be quite subtle.
Test it with something like a sine wave. If it's adding many harmonics you'll notice it then.
I'd imagine the fact it's 8 bit and especially the variable sample rate would make a rather bigger difference.
