I like season 1 to 3 only;
plot, theme and actors completely changed after S03E18.
may seem old and boring to start with but gets better and better, from 1 to 3 leads up to amazing end.
*Very good: Scenarios, Entertainment, Secret agent series, strategy, technology, language, beautiful women, psychology and relationships. Some very good actors and caricatures :-)
Not at all like the movie 'La Femme Nikita'
only negative was the 'over the top' killing of team members who made mistakes.