"... is not a one size fits all model ..." - I think this is very true. In my case, we had an existing product line that our team developed and revised for a long period of years, in use at thousands of locations. We used an iterative process that made frequent releases, etc. But it wasn't "Agile!". So new manglement comes in and decreed "Agile!". However, a lot of our work was fixing bugs, mixed in with occasional new features. We did complex things in our software, and bugs sometimes took a while to figure out. So a lot of the work was really hard to assign points to, etc. It really wasn't suited to "Agile!" as defined by manglement with the required scrum masters. A second side effect was that "Agile!" became a way for manglement to micromanage everything we were doing, and to force their design decisions on the dev team - kind of the opposite of what Agile intended. I got laid off and found a new job, so no longer my problem, thank heavens :)