Writing for a TV is a skill, and not one that many have. Having to maintain pace, coherence and continuity within sharply limited six or seven-minute segments is a remarkably hard thing to do. That the writers of 24 succeed, and have done so over several years, and more in a context that imposes even more limits --the action in each episode takes place in real time of the hour, so that each TV tear ultimately is composed of twenty-four consecutive episodes, all making up one full day-- is even more noteworthy.
And they DO maintain the dramatic interest at a fairly high level. That's a notable acvhievement. In some ways, Season One remains the best of the series, although later years introduce some compelling characters.
But as good as the writing is, it's still good only in the context of television, where the general level of dramatic (and comedic) writing is terrible. In part, that is because network writers are, as a group, limited in their knowledge of so many of the subjects they write about. Worse, they all, or almost all, have a tendency to use the mindless cliches of TV land, when faced with the need to develop a situation. A case in point: Law Enforcement personnel are trained NEVER to give up their weapons in a hostage confrontation, for obvious reasons --drop your weapon and you have effectively become a hostage yourself-- but in 24 that happens all the time. CTU is, on the face of it, the most incompetent organization ever: Over the course of several seasons, it has twice been attacked, each time with horrific casualties; there have been at least half-a-dozen moles acting within the unit, and on two occasions, lose a much-needed witness to a shooting, once by the widow of a slain CTU agent, who finds her husband's gun in his desk while cleaning it out, and once by a teenage girl, a victim of a sexual predator, who kills him with a gun in his apartment after he is captured by CTU and while he is preparing to lead them to the other perpetrators. Both scenes are preposterous: No organization would leave a weapon, and a loaded one at that, among an employee's effects, and no competent law enforcement would fail to immediately search for weapons upon securing a crime scene. In addition, CTU is always losing a witness or suspect they're holding or transporting to ambush, to thr point where you can almost bet with certainty that if a bad guy is captured a few episodes before the last, he will escape, somehow.
But that's how the writers advance a story. Does it take away from the overall effects of the drama? It depends on who you are, I suppose. Most people --as evidenced by the show's popularity-- are undismayed by such things. Even I can overlook them, or at least suspend my displeasure, and enjoy the narrative skill and the fairly good acting --Kiefer Sutherland's performance, overall is excellent, and Mary Lynn Rajskub, who does not appear in Season One, is a treasure.
Contrasting 24 with another popular and long-running series from roughly the same period, Lost, 24 is much better written, far more cohesive and, for the most part, more believable. I would advise that, if you buy or rent the series, that you draw it out and not view too many episodes at once. Things get rather breathless if you do.
Dspite its flaws, 24, for a network TV drama, is a fine effort, and makes for an enjoyable evening.