I step mash a lot because I am a lousy judge of hitting my mash temperature correctly. I heat my strike water to 170°F, then drain it into a cold cooler mash tun, mix in the grains, and next thing you know, the mash is stable at 143°F. So I let it sit for 60 minutes, add a boiling water infusion, and get it into the mid 150s for another 15-30 minutes.
I have also hit my strike temps in the low 150s, and done single infusion mashes. I think this is good for most ales and lagers, but I do think I am getting a tad crisper beer for my pilsners and kolschs with the two step mash. I have not done a side by side to support this.