There are so many reasons to watch this outstanding series, but at the top of the list is the outrageously unprecedented performance of Tatiana Maslany. She was a brilliant choice for the lead.. she COMPLETELY 'owns' all her numerous character(s). For someone just past 30yo, she's already got a long list of productions to her credit. But here in OB, she truly makes the world sit up and take notice... she's flawless in a career defining role. She has by far risen to a performance level unmatched previously. And she does it so seemingly effortlessly and flawlessly that you just keep marveling at the level of her acting ability. She is most always on screen for each and every episode and even though all of her characters have that similar 'look'.. you see them as individuals, and you truly believe they are. It's a very addictive draw for the show. All of the cast are exceptional, as is most all of every part of this unique series. Not usually a fan these fringe productions, but this one is something truly special. It has all the proper elements in the right places and times. Very hard to do, they make each new episode appear unique and interesting, and TM is not alone.. the ENTIRE cast is stellar. It's dark mood could have less appeal to many, but it well suits this very exemplary series. It's always great to come upon a seasoned series that's so worthwhile and still going strong. You just cannot wait to catch-up to the last aired episodes. This one has jumped up really quickly to near the top of my favorites list. If it does end after the fifth season, it will still go down as one of the finest TV series of all time. To be watched over and over again by a growing legion of loyal fans. Bravo to all invoked in its creation and production!!