Made my very first (similar sized) comparison today - a friend from our neighbours came to visit from Scotland and brought his Swarovski EL 10x32 along. I am not a professional reviewer off course but I hope my opinion can be usefull as well:
Zeiss was brighter than SW but the colors in the SW are more saturated, overall the image is very enjoyable in both. The image produced by the Zeiss is slightly better as there are no signs of CA.
Zeiss is very ergonomic but the SW is just perfect - even with the 10x it is easy to hold them steady. Eyecups are better in the SW as well.
Focus is a large difference, for in flight the Zeiss is way better due to its faster focus, the SW on the other hand is more tollerant.
To me both are excellent and I am very happy to own one of them, it would be difficult to choose from - I might as well pick blindfolded, both are just very good.