I have now watched a goodly chunk of the new Netflix Original Series Grace & Frankie, and I have opinions.
If you're the "tl;dr" type, here's my take in brief: the show is entertaining to watch. But do not have expectations of it being Arrested Developent.
The setup is simple, and explained visually in a great opening animation with a crumbling wedding cake with multiple toppers (to Grace Potter's cover of "Stuck in the Middle With You"):
Jane Fonda (Barbarella [sorta NSFW]) is Grace, who begins the show as something between Mad Men's Betty Draper and Arrested Development's Lucille Bluth; she's an image-conscious WASP who self medicates with a lot of alcohol. Grace starts the show married to Robert (Martin "I am so proud of my successful actor son Emilio Estevez" Sheen).
Lily Tomlin (of pre-breakup AT&T fame) is Frankie, a granola-crunchy woman who took many of the 1970's new agey fads to heart. She starts the show married to Sol (Sam "Old Glory Robot Insurance" Waterston).
However, by the middle of the first episode, we learn that Robert and Sol are not just partners in their law firm, they've been having an affair with each other for the past twenty years, and now they're coming out of the closet to divorce their wives and marry each other.
It would be an understatement to say that this is news to their wives (and their kids). Both Grace and Frankie are cut adrift, trying to put meaning to their lives, and also both trying to cohabit in the beach house their husbands went halfsies on years before; previously it was a refuge for each of them in turn, but now, with the men living in Robert and Grace's former home, both Grace and Frankie seek the comfort of the vacation home.
This sounds like the setup for some wacky hijinks, and some ensue (there's a pretty good gag setup in the first episode where someone semi-accidentally ingests a combination of peyote and muscle relaxants), but despite having the setup for straight comedy -- including Grace and Frankie's children, who have sitcom-ready quirks and backstories -- the show isn't meant to be a comedy like Arrested Development or Modern Family, two shows that generate humor every so many seconds from family drama.
This is more a mildly humorous meditation on being older and having one's life change unexpectedly. Grace and Frankie knew what was going to happen for the rest of their "good" years; now they don't, and it's tough having to even partially reinvent yourself after you're eligible for Social Security.
On its own merits, Grace and Frankie is worth watching. Jane Fonda and Lily Tomlin inhabit their characters; as a "free spirit," Lily Tomlin's Frankie gets the more interesting things to do, but they're both really good, as are the supporting cast. You watch to see the plot unfold and talented actors practice their craft; you do not watch because you are expecting to laugh on schedule.
I'm really impressed with the genre-bending nature of Grace & Frankie; it's a half-hour show formatted like a comedy that refuses to be funny if it doesn't serve the story. This a great example of the kind of show that Amazon Prime and Netflix have allowed to be made where previously network executives would have been perplexed as "who the show was for." This is an interesting piece of fiction that definitely deserved the investment that was put into it.