I have read this entire series far more times than I might possibly count, much like a dear old friend, I simply cannot bear not visiting with him and "catching up," time and time again.
Donald Clayton Porter started this masterful series and in my opinion; when in later storylines he characters fade somewhat as Mr. Porter continually pushed out new editions it seemed to dilute the perspective of the original mind-set. In all honestly, after #10 I begin to lose interest and the it just feels to be too much along the lines of pure pulp media and like he is banging away at the keyboards strictly for the sake of monetary gain. I am not an idiot, of course that is why he writes in the first place, but the lineage simply cannot compare with Renno, the "White Indian."
Don't misunderstand me, I still own them all and love them dearly, it is just that I have read 1-10 probably a dozen and a half times each, the rs read just the once.