C. S. Lewis called Styrbiorn the Strong the best Viking novel he ever had read. When I read it years ago, I certainly enjoyed, but I had not yet encountered the actual Icelandic sagas in translation, nor Poul Anderson’s pastiches of the same.
The Worm Ouroboros, read at about the same time, was wondrous.
Last summer I read Mistress of Mistresses. I liked it, but I’ve never read anything else like it. It’s so peculiar, I find it impossible to “recommend.” It’s not exactly “adventure fantasy” (The Worm Ouroboros is more along those lines.) I’m eager to get to next in the trilogy, but, Eddison’s writing style is so demanding, I’m not quite ready yet.