For me the biggest difference would come down to dealer support, I like the Stihl dealer, but he’s 45 minutes away, the Husqvarna is 10. I personally love the 562xp, the difference between the 2 seems so negligible it almost seems like the best deer rifle caliber argument, they all have merits.
Personally, IMO, go with the best/closest dealer.
Last saw I bought from a local dealer was a 371XP, in 1998. Last 3 new saws I purchased came from the classified ads on here or OPE. Can't say I've ever really needed dealer support for much of anything.With these two particular saws you really can't go wrong with either. I would still favor the 400c and I have owned both(albeit Mk1 version), but ai wouldn't sweat it if I only had a Husky dealer near by.