>>4486018OM-5: Better AF, better weather sealing, RAW pro capture, long exposure helpers (live time, live comp), star auto focus, insane IBIS
Fuji: More expensive, AF not that great, IBIS only on premium bodies, questionable weather sealing (again only premium bodies), the smaller cams (OM5 sized) dont have IBIS and weather sealing
Image quality wise they don't differ that much. Both are baby sensor so you get noise no matter what. But for low noise you got a real Nikon camera so you're covered
Fuji is very over-priced right now. At 50% of the price they sell at they would make more sense