I would go with a luppie in that compariosn, just due to my knowledge and general availability. Also support seems to be very very good from my personal experience.
btw, I personally like Nikon Monarch series, so I'm really bias towards Nikon and would thru a Nikon in for comparions.
On the comparisons questions, I would reallly actually go to the store. To many variables to discuss here, but with regards to which one is brighter or clearier, I would also ask my self these questions;
> how many clicks @ 100yrd 1/3 , 1/4 or even 1/2,............
> what type of recticles do they over
> how does the field of view compares at min and max power
> will they change recticles ( mfg ) and what other recticles do they have and if yes, how much to do so
(e.g german, mildot, crosshairs, dot,etc..)
> and finally which one do you like & will Zeiss give you similar support at 2 10 or 20 years later
I betcha 100bucks ( okay no bet ; ) ) that Leupold has more options & overall easier to get support for.
Now if both are really $400.00 that would be what I would looking at. Along as others, but those two models are very similar and really equal into so many ways.
One's opinion would be that, "just one's opinion".
note: Since you gave 2 scopes with differences in objective size 50 vrs 40 , those are not going to be judged the same imho