I've worked in 3 of the biggest rails codebases in the world (Shopify being the last) and I can say from experience that rails legacy monoliths are infinitely worse to work with than some awful, but harmless, sea of struts XML legacy.
I find this really interesting, and meets my (limited) Rails experience and (extensive) Java experience:
I found it hard taking over an existing Rails project - it felt frail to me, that any small change might have unexpected consequences.
Whereas when I've taken over Java projects - or come in late to an existing team - I felt quite confident getting started, even if it is a bit of a mess.
