Nicky (Elizabeth Banks) and Chloe (Jessica Biel) are estranged sisters living in opposite worlds — Nicky, out in Ohio, where she's a recovering alcoholic and Chloe, a master-of-the-universe media executive who splits her time between Manhattan and the Hamptons. Chloe wants nothing to do with her troubled sister, but they're set on a collision course when Chloe's husband Adam (Corey Stoll) is murdered at their beach house. Because Chloe has been the guardian of Nicky's son, Ethan (Maxwell Acee Donovan, "That '90s Show"), since he was a little boy, Nicky arrives to offer both of them moral support. After two detectives from the Suffolk County PD, Nancy Guidry (Kim Dickens, "Deadwood") and Matt Bowen (Bobby Naderi), launch an investigation, suspicion quickly falls upon Ethan. A lawyer is hired (Gloria Reuben, "ER") who wonders about other potential suspects.

This 8-parter, based on the 2019 novel by Alafair Burke, is now streaming.

 What are the odds? Two limited series filmed on Long Island, both about dysfunctional sisters, and both streaming at the same time? This sort of thing doesn't happen often, so let's get down to business. Summer's here, and viewing choices must be made: Which crazy-sister-on-Long-Island show should you be watching this weekend?

"Sirens" arrived May 22 on Netflix, where it has become the second-most streamed series behind "Raw." My review called "Sirens" a "big beautiful bore," based in part on the mic-drop of a finale. But beauty in a TV series is nothing to be dismissed, and "Sirens" did make particularly effective use of various LI locations — Caumsett State Historic Park Preserve, Lloyd Harbor, Southold.

"The Better Sister" does as well — Bayville, Oyster Bay, Port Jefferson, and so-called "establishing" shots in the Hamptons — except that this is a murder mystery, so the colors have been bled, or rather denatured, to match the somber tone. As a viewing experience, "Better Sister" is therefore largely flat and uninteresting, at least when it goes outdoors.

Advantage "Sirens."

"The Better Sister" was created by Olivia Milch, daughter of David Milch. He's arguably the greatest writer — living or otherwise — in TV history ("NYPD Blue," "Deadwood") and she has learned well from her father. "The Better Sister's" dialogue has a crisp, sharp, natural vibe — a sense that the people saying the words have lived them or at least made an attempt to understand them, which doesn't always happen in TV. Biel and Banks are excellent  as is the rest of the cast. Like Meghann Fahey's Devon and Milly Alcock's Simone from "Sirens," both play fractured people trying to salvage the one true relationship that got them through — if not quite past — the trauma of their childhoods. You root for the sisters of both series, but the relationship that feels more organic, or at least more nuanced, is Chloe and Nicky's.

Advantage "The Better Sister."

So which to watch? Regrettably, "The Better Sister" is ultimately hurt by the bane of this streaming era — too thin a story covering too many hours; its pace starts to slacken by the 4th. This is the better show of the two — also the one with more Long Island cred because it's actually set here — but "Sirens" may be the more watchable.

 If you care about craftsmanship, then your choice is clear. If you want something that moves quickly (over five hours) and which ends with a "huh?" instead of a punch but at least looks great in the process, then your choice is clear as well.

Or you could always watch both. What else have you got to do this summer anyway?

Sharply crafted show, but far too long at eight hours.