The Glycerin 23 is Brooks' premium daily trainer, running on dual-cell nitrogen-infused DNA TUNED foam — large cells in the heel for the landing, small cells in the forefoot for the push — with 2 mm more foam added up front this generation, which is what brought the drop to 8 mm.
It suits you if you want plush, distraction-free daily miles a step below the max-stack shoes: the Glycerin has always been the "nicest version of a normal shoe" pick, and the 23 keeps that exact job.
It is not light at about 301 g and it is not a workout shoe. If most of your week is easy and you want it to feel expensive, this is the one; if you need the shoe to hurry, look at the Hyperion side of the wall.