Once upon a time, I used Drupal for my blog. One of the reasons I used Drupal is that I subscribe to the philosophy of "eating my own dogfood." One of the organizations I volulnteered with had a need for a website and, after some discussion, the ability to manage their own content. Drupal seemed to meet the needs at the time. This was because there weren't a lot of (mature) tools (back then) for managing blogs (other than Wordpress) and content.
So I used Drupal for several blogs and helped some friends setup their own blogs. And I used it through multiple versions of Drupal Version 5, Version 6, and Version 7 with different modules as my needs changed. However, I started to notice that some of my content looked different than older content.started to look slightly different. I used both fckeditor and TinyMCE for some formatting, as well as editing content through several different themes which may have impacted the formatting. I really have no clue why some of the content was slightly off - but it made editing the existing content more challenging.
I also was spending more time upgrading Drupal (fixes for different modules and security patches for modules and Drupal itself) then I was creating content or doing work or research. It wasn't a lot of time, but it did take time for me.
None of this is to blame Drupal. This is just an explanation for two of the reasons I decided to leave Drupal. And these may be MY issues, and not problems with Drupal as I altered the modules, configuration, and content over time. There was also a third reason I chose to migrate away from Drupal....I had started monitoring my website for outages which provided the added benefit of giving me page load times. My web server also ran a SMTP relay and a database server, so I was not looking for huge performance, but I discovered that my website was taking up to 1.5 seconds (and sometimes longer) to load.
While looking at alternatives I discovered that converting to a static website would significantly reduce the load time for my content. (In simple terms, loading straight HTML would be faster to load than dynamically generating content from a database and formatting it on the fly.)
All these things really combined together, at a really good time, for me to make a migration away from Drupal and to a static site generator. And that will be another blog post.