Most people that get annoyed by Ida didn't even watch further then the first 2 episodes. Don't get mislead by all those bad reviews, if u are looking for a new serie to watch try this one.
I myself didn't get annoyed by Ida, I don't know why so much other people do. It was clear for me from the first few episodes that see had a fatal sickness, they also explained why her personality was that way mostly because her bad social skills because she hadn't a lot of real life contact with people only over the internet.
I give the serie 7 stars. I like the characters and in 6 episodes u are able to learn about them. There are some random things that were unnecessary, from the top of my head one where Ida gets visual emoijs out of nowhere that don't really add something and they didn't do it often enough to let the viewer really get it.
The serie is about a cult and it has a few deeper meanings that are really fun to get when u get further into the series, really fun plottwists. I did get the feeling that the last few episodes had a big increase in pace, it didn't feel rushed so it isn't a bad thing but u could not really lose your attention otherwise u could miss something important in the story.
It's of course ur own choice if u want to watch this serie, but please don't get influenced by the bad reviews. It isn't that bad as they say. Serie is a good choice when looking for something to watch, only 6 episodes, try to get to 4 if u don't like it by then I don't know what went wrong.