Sonos don’t publish data like this, so unless someone like Peter P has measured them it’s going to be a subjective answer. You could buy and home trial them, and listen for yourself. 

You would then have to decide - if noticeable, is it for the better or worse? If for the better, is it worth the extra spend?

Good luck!

I heard a pair last week on display at a Sam’s club. Even with such an open space, I heard a deeper, tighter bass at medium volume than the ones I have at home. The other difference is it had 2 tweeters for stereo which will also help output more highs vs the one tweeter in the One SL. The sound stage was def wider as well.

check this out Ratings Sonos One vs Era 100

There may be another upgrade path to consider, that I would take if I needed more heft to the One pair - add a Sub mini to it. In addition to the obvious, a Sub addition will clean up the midrange on the One pair, midrange that is more relevant for most of music listening than the high end.

I have a gen 1 sub, arc, and the two One SL’s. Do t want more bass.. want more treble. Unfortunately, Sonos won’t give us more. They must listen to rap and hip hop to have so much bass. 

I am curious as to why you wan’t more treble. As it is if you are anywhere above 30, and like most people, you can’t hear much above 14-15 kHz anyway! 

What kind of music do you think suffers from the One units not putting out the high frequencies in a way that allows you to hear all of it?

What happens when you turn the “Loud” setting off, raise the treble, lower the bass and the sub levels, turn up the surround levels and set them to “Full”, and then on the speech enhancement? You should get highs all day long this way. Adjust to your liking.