My thoughts on this so far, having reached episode 7, is that... it's just not very good.
Which sucks. I thought Hill House was great, with full-bodied characters, interesting stories, places and motivations. The horror was incredibly balanced with the drama. Even with its rough edges it had these incredible, stand out moments, and maintained intensity even (and sometimes especially) in its quieter moments.
Bly Manor on the other hand is superficially following in a lot of the footsteps, understands how to be loud and quiet, and is visually fantastic and smart, but the core of it feels so slow. It's unable to prop each of its characters up at the same level and doesn't maintain the energy of the first series. Its scares are weak, unreliable, telegraphed, and... frankly, uninteresting.
It sucks because I *like* it. It does have these moments that are brilliant, acting that is nailing everything, and at least one episode (so far) that taps deeply into what made the first show great in my eyes, but it is too slow. Even when it kicks up the pace, it feels like its reaching for something it never finds. The drama is overbearing here and stuffy.
I'm hoping it will all come together in the end and have a strong couple of pay-off episodes, but at this point I'm not holding my breath.