I led an engineering team building validated systems that supported GxP processes in life sciences and found that a Shape Up-like process produced the best balance between delivering software that could be validated[1] and speed. I only came across it after several years of trial and error, but I was amazed at how it almost exactly described what we ended up doing.
A side effect is that work-life balance is amazing once you get this process working. If you know exactly how much work you need to do and when it needs to get done by for the next 4-6 weeks, then you can pace yourself much better. When you plan 6 weeks at a time, someone going out sick or taking some time off has less of an impact than when you plan 1 or 2 weeks at a time.
The customers and end-users know what to expect and when they'll get it; everyone gets more predictability in the process. Yes, it takes 1-2 weeks of planning at the outset, but we used that downtime for the engineering team to catch up on tech, build some experiments, work on side projects, or do research. (No refactoring since the validated process requires us to plan and document all code changes that make it into production)
I recommend it for any team that wants some sanity in the processes.
[0] https://basecamp.com/shapeup
[1] Validated in this context means that every feature, function, and infrastructure component can be traced back to a specification through the full lifecycle from design to install to post-install verification and operations.