Exquisite, cozy, at times funny, at times sad, and unforgettable. I won't bore readers with another summary of the story; they're abundant on this site. I will say that with Isabel Archer, James earns his place in the canon with a proto-feminist (yes, I said it, proto-feminist) novel of a remarkable, if hard to describe heroine, who is faithful to her idea(l)s, rejects the affections of strong (but good) men, and suffers unnecessarily at the hands of a Machiavellian cad and an equally manipulative woman. 
 If you don't like long novels--avoid this one like a plague. If you don't like novels written in style from another era, get thee hence! If wordy, complicated sentences are anathema to you, you've probably already stopped reading this mini-review. 
 If I were to advise a reader at all, I'd suggest reading it in as short a period as you can. Bite the bullet, finish it off keeping as much in mind as you can. I'd also advise reading it on a Kindle (for the built-in dictionary) or, at the very least, keep a dictionary at hand. I hope you enjoy it as much as I have; and if you don't--if you read the wrong book for you (this one), please, please, don't say James is an idiot (or some equivalent) or that the book is just boring (or some equivalent)--instead, face the fact, you read the wrong book.