...not considering tone, likability, delivery or whether or not they favor the opponent, etc.
Strictly notice the ability to identify blocking schemes, receiver routes, penalty and offender (well before the ref announces) and blitz/pass rush & coverages plus adjustments - these stand out as the ones that can quickly identify and relay the technical aspects of a play the best:
Danielson and Collinsworth in particular are so quick (even with spotters and earbud feed) on the call and rarely miss - Danielson's preparation is unparalleled.
Also, IMO, best play by play on basis of technical/accuracy (i.e. not tone, bias, likability, etc):
1) Brad Nessler
2) Al Michaels
3) Gus Johnson
4) Dick Stockton
5) Joe Buck
This post was edited on 11/14 at 3:18 pm