I first saw JAG back at the start of Channel 5, & enjoyed pretty much everything I saw of it. Season 1 sets up the premise nicely & it is hard to believe that NBC cancelled the show. Fortunately, CBS picked it up, & a further 9 seasons showed what a wise decision that was.
The pilot episode is superb, with the great Terry O'Quinn as the CAG, & most of the rest of the season is fine, but it is let down by some real stinkers such as Déjà Vu, War Cries & The Prisoner. Set against that though are some great shows such as Shadow, Scimitar & any of the episodes with the incredible Andrea Thompson as the scheming & super-sexy Commander Krennick. It's also worth noting that for the sake of continuity, the episode Boot should be watched after the episode Defensive Action, or Harm's promotion & some of the other comments at the start of Boot don't make sense. Similarly, the season closer Skeleton Crew ends on a cliff hanger that is completely ignored at the start of the second season (a casualty of the aforementioned change from NBC to CBS). I understand though that there is some form of closure offered in an episode in Season 3. It is a shame though that the extras on the Region 1 release have not been carried across to this version.
All in all, if you like NCIS, you will enjoy JAG, particularly this first season. Well worth buying & watching.