Confession time: I liked (and still like) this show a lot. Sure, it was obviously made - ahem - possible by Mulder and Scully and often wasn't quite as well executed but it seemed better thought through than Chris Carter's sprawling epic and the "history as we know it is a lie" hook really appealed to the geeky historian side of me.
The, admittedly improbable, conceit of the show was that pretty much ever significant event in post-WWII history was somehow connected to a covert alien invasion plan and the attempts by the top secret Majestic 12 organisation to, using all means necessary, to keep it in check.
It was a bonkers premise which frequently strained (or snapped) credibility but, at its core, was a really neat idea. The show's first (and only) season spanned the sixties but the master plan was that each subsequent season would have covered subsequent decades until the show came right up to date with the millennium. It would have been awesome.
The critics were, not unsurprisingly, pretty harsh and most dismissed it as another in the succession of FILES knock-offs that cluttered the mid-nineties schedules (heck, even BAYWATCH NIGHTS went supernatural in its seldom-seen second season) but I think they were a little too quick to dismiss a show that had the power to get you thinking a bit.
The ratings were never good so the producers were - ahem - encouraged to make some mid-season course changes (notably adding Jeri Ryan, as a Russian Mrs Peel) to the existing ensemble but these, for the most part, did lift the show by challenging the viewer's perceptions of the format and suggesting that no one was safe from the unfolding battle with the alien Hive.
Eric Close managed to shrug off the failure and carve out quite a small screen career, most recently on the far-better-than-it-should-be NASHVILLE.
By all means seek out the DVD box set. Once dismissed as being 'unreleasable', because of the copious amounts of expensive-to-clear period music, the show has now been released on R1 and R2. If you have the choice, plump for R1 as it has a much better set of really rather good extras. The show deserves no less.