What are pros and cons of Hackathons on implementing a DevOps culture?
If the project is for a startup's minimum viable product or some other sort of sanity-check/proof of concept effort - hackathon before DevOps is often recommended - basically in the "fail-fast/fail cheap" lean startup strategy.

Some might recommend hackathon before DevOps in other situations as well, for time-to-market reasons. But if DevOps doesn't followup fast enough that initial market bridgehead can easily collapse. Possible reasons for that include:


that early momentum can be ephemeral - easily lost as soon as the DevOps process starts to be established ("it's too hard, it's slowing us down")
typically hackathons cause accumulation of technical debt. The cost of managing and eliminating it can outweighs the benefits of that early momentum.