I happened to read about various B2B attribution models in a CEB Global article last year. The URL for the article was https://www.cebglobal.com/blogs/how-marketing-is-finally-learning-to-get-a-good-return-on-its-spending/.
However, when I checked that link today, it goes somewhere else. Luckily, let me reproduce the following key graphic from this article:
As it says, First or Last-Click Attribution models are least accurate but most popular because they’re the easiest to implement; and Algorithmic Attribution model is most accurate but perhaps quite hard to implement, especially if you have limited amount of data to train the models on.