I won't even consider owning another Woods mower.  And it was a BB840 that prompted my poor opinion of their product(s).  I had issues with the gearbox, paint, 3-point hitch framework, and Woods failure to honor warranty.  Less than 2 seasons of use and it was literally JUNK.  
The Bush Hog 28X and 29X series mowers are UNDER rated.  They meet or exceed my expectations of a heavier duty rated mower.   I've logged 4-1/2 seasons of use on the Bush Hog mower (287) that replaced the Woods BB840.  It still runs like the day I first bought it.  
IMHO, it's not even a question which one I'd buy.