Shine Communications, Bite Communications and Lexis PR all shot up the 2010 rankings from last year, to be placed sixth, seventh and tenth respectively.
Brands2Life came 15th in the table, also achieving the top three-star grade.
However, Freud Communications, Consolidated PR, GolinHarris and Trimedia (now merged with Grayling) all failed to feature in the top 100 this year, despite making the cut last year.
The Sunday Times list was topped by IT firm Softcat.
The results were assembled via a questionnaire that asked employees to rate their employer on several categories.
These included how they felt about the stress of their jobs; to what extent they felt challenged; how staff felt towards their immediate boss; how happy they were with their pay and benefits, and whether they believed their firm gave back to society in general.
Shine Communications rose 27 places to take sixth position after being praised for having a benevolent management and giving employees space to grow.
The firm invests 13 per cent of annual profits in staff training and a quarter of the profits are shared with staff.
Bite Communications claimed seventh spot for its strong management, team spirit and personal growth opportunities.
The staff-nominated 'star of the month' has the chance to win a secondment to one of the agency's 11 offices worldwide.
Fellow Next Fifteen-owned agency Lexis PR rose from 100th last year to a very creditable tenth this time. It is the fifth year in a row the agency has made the list.
Healthcare agency Chandler Chicco Companies appeared in the list for the first time at number 97.
Blue Rubicon slipped from 18th in 2009 to 42nd this year, The Red Consultancy came 52nd (down from 41st), while Nelson Bostock was 63rd (down from 20th).