[zulfishah]

Just to add to the "anecdotal" evidence: I watch App Store rankings for my app like a hawk, and aside from the comment about rankings not changing as often, maybe once in 2-3 hours, I haven't noticed any other changes. My app is rated very highly (4.5 for most recent version), and it's ranking inside Business category is consistent with revenue as before. Haven't noticed anything different.

[nasalgoat]

Our app, which is also highly rated, jumped significantly while our lower-rated competition dropped.

I think this is a good move - it will make everyone work harder to make a better quality product.