OK, had the scope out last night and compared the XF 8.5 with the 9mm Genuine ortho.
The ortho gave me a me “brighter" image of Polaris (and companion), Venus and M94 most of the time. I guess the smaller FOV is the number one reason for the difference in image brightness between the XF8.5 and 9mm ortho. The smaller FOV lets the object (and its details) really pop out. Sharpness was almost identical to me.
Though the ortho gave me a brighter image I kept using the XF for the rest of the night. The larger ER and bigger FOV makes it a nice EP for DSO-hunting with hand guided telescopes. I bagged 2 galaxies of magnitude 12.6 last night without difficulties (NELM here is 4.8 so 12.6 is really faint for me
).