How bad are the knobs?
Not bad. They (the knobs themselves, not the encoders) just feel a little bit cheap (I would have preferred a bit more texturing).
Is the LeCroy firmware better?
No, not really. At the end of the day it's the same firmware as the original Siglent firmware (both are made by Siglent, LeCroy only provides the name anyways). LeCroy at least provides some changelog, though.
However, since the LeCroy WaveAce 1000 is actually a Siglent SDS1000CML (not the CNL) I now have a setting to enable half speed memory (which I guess my CNL doesn't have). So far however I haven't seen any drawbacks.
And one can easily flash back and forth between Siglent and LeCroy firmware anyways.
Any photos? What about the display? Is it good?
The display is quite good, albeit it has a lower resolution (480x234) than a modern smartphone. But it's nice and clear, the menu structure is good as well, overall a nice entry level scope and certainly worth its money.
If I find time in the next days I'll do a more thorough review with pictures.