>It has a great backwards-compatibility story -- a lot better than Python's, for example, which I use in my current dayjob.
I think this is a really important point. I worked intensively with Python for years, but it was a deep disappointment to see how little the core devs and the community care about backwards compatibility in the 2/3 transition, and things have not improved. That might be due to what Python is dominantly used for today (The Numeric/Numpy transition which happened around 2000 was totally different). Breaking things every few years might be OK for unicorn startups or companies that move fast and, well, break things, but there is a lot of valuable programming from people and in organisations which can simply not afford, or do not see it as a priority to re-write mature algorithms every few years.
I think this is a really important point. I worked intensively with Python for years, but it was a deep disappointment to see how little the core devs and the community care about backwards compatibility in the 2/3 transition, and things have not improved. That might be due to what Python is dominantly used for today (The Numeric/Numpy transition which happened around 2000 was totally different). Breaking things every few years might be OK for unicorn startups or companies that move fast and, well, break things, but there is a lot of valuable programming from people and in organisations which can simply not afford, or do not see it as a priority to re-write mature algorithms every few years.