I went with Date, but I abandoned that game because my economy went crazy (food deficit).
The I tried with Shimazu, but it was VH and I left it after conquering the isle to wait until I learn some more.
I also started a H/H with Uesugi, which went surprisingly well considering all the posts about them being difficult - I still have the save to continue that.

My actual longest campaign is with Chokosabe and I am past the divide well on my way to win it (H/H).

As you can see, I like to play with things...