Comparing DL BizElite (AMS-ATL) with their alliance partners AM Clase Premier (ATL-MEX + v.v.) and AF business class CDG-EZE and GRG-CDG:

DL Biz Elite is streets ahead, with superior space, comfort and cabin service. AM is adequate, restricted space (in a first class?) - wouldn't like to do longhaul. AF lags behind, space OK but ventilation bad - and until November 1 they still allow smokers! - they still have a row of F, which looked empty when I flew with them.

VS have a 3-class layout, with Upper Class (= business class) the top level. Haven't flown this year, trip coming up in 2 weeks. Until now, I have rated VS the tops, way ahead of BA biz, for example. (I haven't tried BA F, but it is much more expensive than VS J, and I cannot compare BA's new J on their single route JFK-LHR starting soon.)