Currently re-reading the entire Dark Tower series for the X time (never kept track). It's quite literally the best thing I've ever read. I personally love long series (Enderverse, Wheel of Time, Farseer, etc) and its a genre blend, also a thing I love.
I tell everyone the same thing about the DT, it may be difficult to get
through the first book, but it just gets better as you move forward.
I just had to chime in and express my passion for the series. It's a series which I've read a number of times and it still pulls me in every time I start it again. Ka is a wheel sai.
Long days and pleasant nights!