Uber and Slack look nice but they're rather slow. After a week, the "looks nice" part ceases to matter and all that's left is the annoyance of waiting 200ms-1000ms between every action.
I agree with that, but also 99% sure the latency in those apps have nothing to do with their graphic design and more to do with these apps waiting for an API roundtrip response before updating the UI, and possibly lots of analytics bloat.
