Ranked in these QuestionsQuestion Ranking
Pro Fast startup
Dash has a very fast startup, this happens because the shell is started a lot of times during boot and dash minimizes the work it does during this process.
Pro Low memory usage, which matters a lot in embedded.
Pro Default shell on Debian systems
Dash is the default shell for Debian based systems (which includes Ubuntu).
Con Doesn't support all bash features
Dash does not support all bash features, sometimes called 'bashisms' unless explicitly pointed at