Triangle is a good show with an intersting premise. It's like an extra-long movie with some intersting characters. I wish there were more strong female characters. Some of the scenes were shot in such a amnner that they were difficult to see clearly (pretty much any scene shot at 'night') - it would have been much better to watch in HD.
The premise of the show is reminiscent of other Star Trek episodes like Voyager's Before and After where characters are inexplicably thrust into alternate realities/timeframes.
Overall, it is a well-written show well-worth the six hours spent watching it. I recommend it to anyone who likes sci-fi.