When comparing Fujifilm X-S20 vs Nikon Z6, the Slant community recommends Fujifilm X-S20 for most people. In the question“What are the best professional mirrorless cameras under $3000?” Fujifilm X-S20 is ranked 5th while Nikon Z6 is ranked 9th. The most important reason people chose Fujifilm X-S20 is:
Large grip with a large battery, CIPA-rated battery life of up to 800 shots.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Large grip
Large grip with a large battery, CIPA-rated battery life of up to 800 shots.
Pro 20 fps continuous shooting
8fps continuous shooting with manual shutter, 20fps with the electronic shutter.
Pro Hi-Speed video
240fps High-Speed Video.
Pro Built-in flash
Pro High-ISO quality
Superb for low light conditions.
Pro XQD card slot
supports XQD 2.0 and 1.0 cards, see Nikon Z6 XQD Card Comparison.
Pro Full frame 4K video
Pro In-body image stabilization
Cons
Con No weather sealing
Con Not all reviews are positive
Here is a critical review: BEST MIRRORLESS CAMERAS OF 2019.
Con Display tilt
The display can not be tilted 180 degrees for selfies.
Con Buffer capacity
Average buffer capacity which slows down performance especially when using older and slower XQD cards.