I sometimes explain it as a bit like the "undo/redo" history in an application like word - but on an entire folder of files. That's an explanation of version control anyway. The distributed elements is a bit hard to find a useful analogy for, there is only so far you can dumb it down. https://guides.github.com/introduction/flow/index.html is a nice article to show people

I'm surprised other people are giving you concrete answers as it is impossible to say. How much have you invested in building the current ROR based system? Are the developers happy to code with both or are they simply steering you towards the technology they know? Magento is a great platform. Extensions are a double edged sword, they can be very good and save a lot of effort. Likewise there are some terrible extensions out there. The cumulative effect of adding lots of extensions can be really bad as well. Ultimately, you are likely to get what you pay for, no matter which platform you go with.