I'm always using the crossfeed setting and consider its contribution to the sound to be quite modest for some recordings and quite distinct for others. However, your description of it is IMO, grossly exaggerated.
The difference in sound that I've heard from different amps I've used provide bigger differences in sound.
Who's to say which of those amps are more neutral etc. Not so easy unless you do very careful testing and comparisons with great familiarisation with a neutral standard with which you're comparing.