Songs with less than 120BPM are rather annoying.
So I have noticed anyway. I am only playing beginner courses, being a beginner in my own right. I have found I do better on songs with great than 120BPM. Those with less than 120BPM, well let us just say I get a lot of Good and Great pop up a lot. I usually hit the button corresponding to the arrow way to quickly.
Faster songs are easier for me. I can more easily attain the beat, if you will. Though anything past 160 begins to get a little challenging. Let's just say I have tried my skill at non beginner songs. To that point, half beats, confusing as hell, especially with a keyboard. I don't even see how you could do that with a dance pad. A controller perhaps.
I am sure there is still much for me to learn. All I know is I just love the music. The songs are all good. I am glad.