I used to work on several SL mixers. They were "okay" but you didn't get that display that you are referring to, and the console had a bit more of an analog desk feel in a way. I never used it with the software, just the desk by itself.
On the SL gen 1 & 2 mixers you only have the LED indicator above the encoder to show the frequency. On the SL 24.4.2 (gen 1) I believe it is a 12db slope, that was changed w/firmware on the gen 2 (AI) series to an 18db slope.