I'm enjoying it, but I'll say that how to do nothing is a better book IMO. I actively recommend that to people. So far I don't think I'd tell someone to read how to save time unless they're already interested in the philosophy/ideas being expressed on consumerism and the relationship of socioeconomic class to how time is spent working, or they just really loved how to do nothing.
So with that if you're not already reading it I recommend the new book- my main criticism thus far is that it feels less focused than the prior book was. I think she was going for a non-linear approach as a metaphor for how time isn't necessarily linear, but something about that doesn't work well here and makes her points harder to retain and follow/connect. Or maybe that's just me. I could see myself rereading both books in the future though.