As for Blade of the immortal, even though I found it kind of slow at the beginning (even dropped it a while) and I wasn't a fan of the artwork, it ended up being one of the best things I've read, few manga/anime I've covered have an ending that satisfying.
It got better and better. The entire second half was a roller coaster that went some places I was not expecting it to and gave you a large cast of really interesting or weird characters and all kinds of incredible action. The ending as you said was great as well and it was not a series that overstayed its welcome. In fact it left you wanting more. It also gave us one of the most detestable villains ever in Shira. There are few characters who made me as angry or disgusted as that fucking guy. When I realized he's raping that one little kid that is helping him I said out loud,"Someone needs to kill this fucking guy already!"