I really liked the cast, characters and the fictional universe the show was set in, so at the time I forced myself to watch basically right up until the end (I jumped ship halfway through the fifth and final season, I just couldn't take it anymore).
There are still a handful of episodes in the later years I remember fondly. Rommie's best episode, "A Symmetry of Imperfection" comes in late season 4, with season 3's "Day of Judgment, Day of Wrath" coming in second place. The military aspects of the premise were never realized better than in season 3's "Point of the Spear". "Harper/Delete", also from season 4, is dumb but fun because Harper was always such a lively character.
But for the most part, everything after Robert Hewitt Wolfe was fired is absolute garbage. The first season is also, in hindsight, wildly uneven. I'd take almost any episode from the later years over "A Rose in the Ashes" or "Sum of its Parts".
The first half of season 2 is the strongest run of the show, which makes the second half of the season that much more painful. Everything about the series looked to be evolving, from the new sets and improved costuming to a greater consistency in the writing and fewer ridiculous action sequences.
And then it all goes so terribly wrong.