I run 175mm stuff, courtesy of restomodding or finding groupsets from the later '80s that made them that long because they got hip to the idea of really tall riders may want longer cranks.
170s can feel like flippin' hamster wheels with a less than ideal setup. Too constricting on the leverage side at times, though the knees appreciate it and spinning is easier.
175s are my normal, and feel good all the way around. Plenty of leverage and easy to spin at a decent clip.
180s feel quite long, and have mechanically more leverage (and mentally a LOT more), though I'll pedal slower of course. Knees notice it, but if you're good with it, they'll live.
172.5s are a nice balance between 170 and 175, having much of the leverage of 175s yet the knee-friendly spinning ease and speed of 170s.