What is better?
Scaling the heights of a small mountain or reaching half way through to the highest peak?
Even when the effort required for the job is same, what is preferred? being mediocre at a tough job or being the best at a relatively easy job?
It guess it depends on personal choice and what matters to a person.
If the person is motivated by success the best way would be starting with a small mountain, conquering it and repeating with a higher peak each time. This ensures both success and satisfaction.
If a person is motivated by the act of climbing itself, the challenge of reaching higher, and not so much by the destination in the form of the peak, it is preferred that the person starts with a high enough mountain to scale and feel exhilarated all through the climb. There is no specific target and the person can scale as high as they can.
So also with work. Whether to join a top-notch company and always on the toes to prove your worth or of join a mediocre company and be a star!