I'm about halfway through both of these, but I think they're both great.
Rhythm of War by Brandon Sanderson (Book 4 in the Stormlight Archives series)
Love him, or hate him, BS is prolific. He somehow maintains a superhuman level of efficiency in writing. This is the 4th of a planned 10 book epic fantasy series. I can't possibly summarize the 3.5 books I've read in the series so far, since each is approximately 1200 pages. Really they're about 3-4 of an average sized trade paperback each. That's not to say they are too long either, with the exception of the first book (a common/unavoidable problem the with epic fantasy genre, there's just a lot you need to say to get people fully invested), they pick up from the first word on interesting storylines and just keep churning.
and
Children of Dune by Frank Herbert (Book 3 of the Dune series)
Dune is one of my favorite books of all time. SOmehow, I've never read the rest of them. I re-read Dune this year, and decided to continue the story. I really wasn't a huge fan of Dune Messiah. I don't want to spoil anything for you, but let's just say it's probably because flaws of the main character are too humanly frustrating to watch unfold. Children of Dune is, so far, as good or better than Dune in my opinion.