Well
I had a lot of problems with the series, to begin with, mostly stemming from how the first series ended. It was there that I began to strongly dislike the series despite reading it because as authors are prone to do, they took it in a direction that made no sense without the explanation of "StarClan's Wooshy-Swooshy Star Power". StarClan had never stricken me as something that should be omnipotent- it was one thing for prophecies, it was another thing to gift powers to three (wait, no, four cats, StarClan can't count apparently).

The first series of books had a charming appeal to them, which is what drew me in. It had a coherent plot and a more realistic feel to it. While the writing wasn't superb, it was great in terms of plot and character development. You had a character who was rivaling the expectations of all the wild cats, a former kittypet clawing his way up the social ladder to prove himself worthy of being a ThunderClan cat. A classic Hero's Journey. He made several close friendships, namely with Greypaw and Ravenpaw, and a few enemies like Longtail and Dustpaw. The appeal of his budding romance with Sandpaw, as well as the remaining feel of loss from losing his first love Spottedleaf made for a great romantic sub-plot. The slowly degrading sanity of Bluestar brought a sense of dread, and the sub-plot of her half-blood kits added to her character in a beautiful way. The uprising of Tigerstar, my favorite villain of all time and his rather entertaining henchman Darkstripe helped carry the plot forward and encouraged hatred for the enemies in such a way that you couldn't sympathize with them even if they had a tragic backstory. Despite the rather disappointing end to the greatest villain in the entire series, it was an enjoyable read from beginning to end.

The second series was disappointing in several ways. It was sloppily crafted. It could have been something that would have added to the story of the Warriors Timeline, but it was really forgettable to me. A tiny blip on the radar, if you will. Nothing about it stuck out, and the only things that affected the next series were the change of location and Leadpool's/Crowfeather's drama.

The third series had a vaguely interesting premise, but the addition of 'powered' cats made everything artificial and typical. The charm that I found in the original book series was lost with the introduction of the "three" powered cats. The fourth series only served to overcomplicate things and after Firestar's death, I just stopped reading. I was disappointed, and I only really re-read books from the first series after that.