The first season is interesting, a little different. I would say "good", with some fun songs. It should have ended there, imo.
After season 1, the plot takes a serious dive, storylines are not well thought out (like her donating her egg) or are simply rinsed and repeated. The songs aren't as good and are no longer integral to the storyline, and many feel like filler as though they have a certain song quota they need to hit every episode.
Many of the storylines after S1 are recycled storylines in different outfits: Rebecca's love triangles, who should she choose this time? This guy, that guy, or that other guy? Paula's two modes: being obsessed with something and ignoring and being rude to anyone that has no involvement with her current obsession, or complaining about how unappreciated she is by the people she was just neglecting. She is by far the worst character on this show for me, because she is almost never reprimanded or held accountable for how badly she treats people, especially Rebecca.
By the end of the series, this show just feels like a vanity project for Rachel Bloom. We are basically just watching her character make out with different guys who are hopelessly in love with her, despite her character having done terrible things to them in the past, and offering them nothing of substance in the present. At some point, when you remember that the actress playing this main character is also the creator, writer and executive producer of the show, it starts to feel weird.
Rachel Bloom also seems to be weirdly obsessed with her boobs, and creates opportunities to bring them up in the show in any way she can. If her character isn't talking or singing about them, other characters are, including child actors, which is disturbing.