Border Terrier or Coton de Tulear? (active small dog breeds)

I live in NYC and am looking to get an active small dog - agility, water adventures, dog parks, tennis balls etc. Preferably not more than 20 lbs, 25 max, but don't want a toy dog (above 10-12 lbs). Can't be yappy, and don't want JRT type of drive. Are Patterdales are driven as JRTs? Reading conflicting info. So far I'm looking at Border Terriers and Cotons - what would you say are the main differences (besides coat type) and pros and cons? Thanks!