Thank for helping out guys. Most has been said already
For more detail do read the comparison of the Zeiss Victory FL 56 and Swarovski SLC 56 WB binoculars here on CN and EL 50 vs SLC 56 in links already provided by SMark.
Here is my bottom line summary on these wonderful binoculars. Of course, YMMV. Any one of these are fantastic with their own strengths and weaknesses.
From Swarovski, the SLC 56's are the brightest, the EL 50's the nicest binoculars and they cost more too.
The Zeiss Victory FL 56's are different from both the SLC and EL.
They have a curved field, which I prefer both day and night to the flat fields of both Swarovski's.
If you are going to use the binoculars mainly during the day and occasionally at night, I would choose the Swarovski 50 EL in the 10x model. It is light, compact and just wonderful for that use.
If you will mainly use them at night and sometimes during the day, the 56 mm models from both Swarovski and Zeiss are brighter and much bigger and heavier than the Swarovski EL 50's. The EL's have slightly better corrected optics than the SLC's, but the SLC's are brighter due to their larger objective lenses and different prism system. That brightness shows at night. But overall the EL 50's are better made and more suitable for allround day/night use IMHO.
But all these differences are minor. Any of these binoculars is superb and will show thrilling images of the heavens under good skies.
If money matters, the SLC 56's have the brightest images and the best value for money.
If money is no object, the EL 50's are wonderful and the smallest, most compact of them all.
The Victory FL's are no longer available new. They went out of production around 2014.