Errr...
Catherine becomes regent in 1559, for Francois II. She more or les gives the power to the duke de Guise, and starts reigning only in 1560 after these become less popular.
She keeps being the major power in French politics until her son Henri III is crowned, in 1574.
So overall she exercised power during 15 years, not 30. She was not the only woman to exercise power as a regent (Marie de Medicis after her, for instance, and she's probably more interesting a character although even less fit for ruler of a civ - at least she tried to seize power against her son). During Catherine's time, France lost all its italian territories. The country had to face violent religious wars, but since she had put the Guise party in power and let them fuel the hatred for one year, and later let her youngest son (probably) cause the slaughter of thousands of protestants, I would say that the net result of her being in power is quite negative. It also ends with the end of her husband's dynasty.
As for Louis XIV , he invented absolute monarchy. This kind of monarchy didn't exist before him in France. He curbed the feudal lords, who were never again a threat to the king's authority after him. The very strong centralisation he promoted is still felt in France today. He expanded the French borders (Alsace, Artois...). He also managed to put his grandson on the throne of Spain, and is an ancestor of the current king of Spain. He also sponsored the arts, built the palace of Versailles with its gardens and fountains...
Finding Catherine more interesting than Louis is a bit baffling imo. She's interesting obly because she's not well-known, she's not well-known because she wasn'tthat interesting to begin with in comparison with many French rulers.