Here's where I'm at standing at 6' tall:
* This past saturday I ran a 5K unshod at 7:00 pace and my average cadence was 187.
* The day after I ran 18 miles on gravel in huarache sandals at 11:20 pace average and my average cadence was 176.
* A couple days ago I did a 5 mile tempo run also on gravel with huarache sandals at 7:58 pace with 177 average cadence
* Yesterday I did a 2 mile warmup and 8 mile run both unshod at 9:11 pace and 181 cadence.
Two years ago I would consider a great 5 mile time to be 43:30 and struggled to get under 24:00 for a 5K and my legs would feel three feet thick after each of those attempts. My cadence at that time was closer to 160. At around 180 my legs feel relatively fresh even after a hard run and I'm able to maintain a lot faster pace for the same effort than at 160. The numbers just don't lie: 180 > 160.
The issue I take with "Well, 180 is what they've observed with pro athletes so it's OK to have a lower cadence" is the evidence just doesn't support that. The difference in my own cadence between 11:20 and 7:00 pace is only 11spm. Even there a lot of that difference appears to be that my cadence is higher unshod than in huaraches. And I've been able to run a lot longer distance far more efficiently around 180 than I ever could at 160. The conclusion there seems to be if you're human then around 180 is the cadence you need to be efficient. If you're an elite athlete you can do 4:00-5:00 pace pretty easily at 180 cadence. If you're me you can do 11:00-7:00 pace at 180 cadence. The difference is my legs aren't as strong or trained as, say, Mo Farrah.
And if you're sprinting that cadence hockey sticks *way* up. Usain Bolt is 6'5" and spins at 260 going flat out. 6' tall sprinters are approaching 290.
All the evidence pretty clearly points to being around 180 is where you want to be if you want to be efficient. And I believe it's even more crucial to step at 180 or higher if you're not as strong or out-of-shape. It's like shifting a bike: lower gears require less muscle power. If you're trying to get into running you'll be better off spinning those legs quick.
A lot of us trend toward a slower cadence because we simply don't run enough but we do walk a lot. Walking cadence is 100-120 so 160 is going to feel faster than that but as you progress if you're still stuck at 160 you're really missing out on efficiency. Your own body type and height will mean you'll be a bit higher or lower than 180 but I'm talking low 170s to upper 180s.
Careful not to be fooled into thinking 160 is good because it feels "more natural" than 180. If you're used to scissor-kicking the high jump the Fosbury flop will feel "unnatural" at first, too. You can get used to any technique but that doesn't mean the technique you happen to be used to is ideal.