I just wanted to chime in and say that I also found the popup very disruptive and annoying. I didn't download the ebook. I bet putting it at the end of the blog post will get you better results (you should A/B test it and do another blog post).
After all, the people that read all the way through the entire blog post are your target audience. These are exactly the type of engaged readers you want to capture.
After all, the people that read all the way through the entire blog post are your target audience. These are exactly the type of engaged readers you want to capture.