Much better? I doubt it. And I'd maintain that if a solid state electronics player started to sound even a little better over time, the electronics "break-in" took place not in the player but in the brain of the beholder, as one psychoacoustically accommodates to the new unit (i. e., becomes accustomed to the sound of said unit).
I propose a simple test for such subjective audiophile phenomena: once the unit is fully "broken in", plug in a brand new one right next to it, level match, insert 2 identical CDs, and cue em up. The subject is then asked to blindly guess which is which, while someone else switches them A/B/A. If you get it right over 50% to statistical significance, I'll give you a cookie.