Ask 50 different people and you"ll no doubt get 50 different answers.
Type of land.
type of work, ie lamping,bushing,ferreting etc.
personal choice on size, coat, temperment.
past experience.
how can you know what the best is or what your favorite is with so many possibilities, you cant have tried/seen them all unless your either very very old or one of the many dog swappers who swap and change and run a different dog every week