I've hade both zooms for about two years now, here's my limited test findings:
1. Baader had click stops, which made it easy for using in binoviewer; Leica has the just right smooth zoom action, a feel of quality.
2. Straylight control: i.e. when a bright star or Moon is outside FOV, any light come into the FOV. Baader is obvious worse, a defocused Vega or Capella is flooding the FOV when it's clearly outside FOV, while Leica is just excellent, not a slightest hint where the star is when it's just outside FOV.
3. Sharpness: Leica is both sharper than Baader, I observe only on-axis with my tracking mount, off-axis is only for finding/framing.
As to darker background, I see it might be interpretated differently, so I borrow Bill's terminology here to divide it in two parts:
4.1 scatter control: i.e background around a bright object (Jupiter, Sirius, etc), Leica is better with darker background, the scatter level is about as my 18 BCO and 10 BCO; Baader is more in level as MV20 and MV24, i.e. noticeable more scatter.
4.2 faint star field: Leica is brighter. My interpretation is slightly higher transmission, because I don't see how an eyepiece can chose tranmitting more star light than background glows, these are all continous light spectrums.
5. in 2" mode, they're practically parfocal.
6. I don't see EOFB in any of them,
7. They both vignette in low mag end, Leica more severe than Baader.
I use Baader in PST (since Leica doesn't come to focus) and for alignment (the less good straylight control is an advantage when a bright star is outside FOV), and Leica for mostly all other Cyclops observations when the focal length si suitable, planetary to faint galaxies, about 150 of my new galaxies down to mag 14 were observed with Leica in C8.
To me, both are excellent for their prices, worth every penny of it.
Edited by YKSE, 11 December 2016 - 06:29 AM.