Which neighborhood - putney or south ken? Help me (London)

I'm going flat hunting Friday - where should I live?

I've narrowed down to 2 major choices and I can't decide. Please give your thoughts.

I'm here on a 2 year assignment so I want to make e the most of it

I'm mid thirties, single, professional woman.
Not into clubbing scene or staying up til dawn. Would like to be in a neighborhood where I could find activities or events to go to and meet other solo expat professionals.
Work is on Picadilly line or can use national rail
want convenience and access to decent markets or casual ships
Enjoy quaint restaurants and coffees

Imagine all rent was equal where would you pick between either....

South kensington smaller more modest 2 bedroom, beautiful area, nearer to central London and Hyde park, with longer commute

Or

Bigger aparmemts with river views and a gym in the building and shorter commmute, but further away from central London and less luxurious neighborhood