I found the trilogy on DVD in a bargain bin some years ago and it became a sci fi guilty pleasure for me & my roomate.
Co written by Bryan Singer and Dean Devlin, this Sci Fi trilogy has fun exploring the myths and theories of the Bermuda Triangle. It is about what one would expect from a Devlin / Singer project - solid moments, sci fi / fantasy moments of varying quality & plausibility and some typical Devlin cornball bits.
As Singer said in a DVD commentary, it was a chance for him and Devlin to 'geek out'. And the writing is just that - fun & geeky.
The trilogy itself is a little less so.
The actors have some good moments and a few questionable ones. Sam Neill's role is reminiscent of his character in 'Event Horizon' but better (I'd rather watch 'The Triangle' than see 'Event Horizon' again). Catherine Bell holds her own, as does Bruce Davison. Eric Stoltz is a bit uneven - he has good moments and a few cringeworthy moments (especially near the end, but I got the impression he was doing his best with a script / scene that needed one more revision). Michael Rodgers is also decent in the context of the production (though there are a couple of moments where either the actor, the script or the director went full cornball - notably the introductory scene when he jumps out of an airplane into the eye of a hurricane. Very Dean Devlin.
Lou Diamond Phillips also does a decent job with the material he is given; on the upside, he convincingly shows the emotional torment of his character's arc & experiences; unfortunately, his character is isolated from the main story until the last 30 minutes. The writing & editing amplifies his function in the series (not a good thing) instead of smoothly integrating him in the story arc. It is obvious his character is there to serve a plot purpose; this hurts the flow somewhat.
The special effects obviously rely heavily on CGI, though this is made up for to a degree with a cool and appropriate color palette and a consistency that almost makes this early CGI work seem like a stylistic choice rather than a low budget hindrance. E.G. it is not a major flaw with the series (IMO).
The music is well done; the opening theme is particularly appropriate for the subject matter and the incidental music hits the right emotional notes - it matches and enhances each scene without being obtrusive; in fact I'd say the music saves the series. A lesser score would make the weak scenes jump out, but the Loduca's score smooths over some rough edges and enhances the more solid moments.
The story: It's a quirky rollercoaster ride with a number of twists and turns - some more effective than others. It rarely drags - a common in sci fi approach, trading deep character development & story consistency for a strong pace; not that it lacks character and story development; in fact, it does more than the average sci-fi mini-series.
Without getting into spoilers, 4 people from different backgrounds are hired by a shipping magnate to figure out why his ships are disappearing in the Bermuda Triangle, which requires them to determine what is really causing the strange events there. They are highly motivated since they only get paid if they find an answer to the mystery.
Along the way, they develop a variety of theories while experiencing increasingly strange events, including unexplained visions, etc. as they get closer to the cause of the mystery. I won't say any more except that they do eventually penetrate the heart of the weirdness and are changed in the process emotionally - the all grow and reevaluate their life choices (an aspect not too common in a typical sci-fi miniseries).
Common criticisms: yes, the series is somewhat derivative (though it throws in some unusual combinations that keep it from being tedious); yes, it has inconsistencies and weak points (some are smoothed over with other elements like the music and pacing); yes, some of the scenes are kinda ludicrous (hey, it's a sci fi mini-series for TV), and the end is not the best (not the worst either - the denouement is the hardest bit with any film, especially with sci-fi).
For a 3 part Sci Fi series, is could be much worse. IMO. Though not the best short run production I've seen, it is better than a lot of typical Sci Fy fare. If you can get past the negatives I've pointed out, ignore the derivative moments and suspend disbelief a bit, you might find that it is a fun little romp with no truly fatal flaws; a bit if a Guilty Pleasure & worth at least one viewing.