I've replaced mine with aftermarket knobs until my replacements get here, which I requested about a month ago. They don't look better, but they don't break. Function before form.
However, I just noticed that two of the memory buttons have radial cracks in them. This amp never leaves my practice room and I change the channels with the footswitch. It looks like the plastic is shrinking. I don't get pissed off very easily about this stuff, but my patience is being tested here. I've notified TC, and we'll see how they handle it.