I'll rank the full battles.
Gary=paul Rivalry settled pretty good teams on both
Harrison -most intense
Tobias- Ash finally gets legitimately pwned. As in the way he lost made sense.
Cameron- Great animation intense battles and types actually mattered.
Katie- aCOTD with 6 pokemon was unheard of til then.
Morrison=Tyson rushed messes that made you really think wow they must suck to be pwned by a swellow ajd corphish.