Are software comparisons considered on-topic here? I mean Ubuntu software of course, and probably software which is specific to it or at least Linux but runs on Ubuntu. And how broad is considered 'too broad' in this case? I mean, can you just ask what is the difference and why you would use one over the other? Or do you have to be more specific than that?
The "too broad" close reason is reserved for open-ended questions that require a book to be written to answer them.
You're asking us to say whether a hypothetical class of question is off-topic without an example. It's entirely possible that you can have a great question that is in the form of a "software comparison", just as it's possible there can be real steamers.
I have no interest in banning software comparisons. Just look at them on a case-by case basis. If questions...
- ... can be answered
- ... can be answered without writing a book
- ... can be answered objectively (or at least with objective rationale)
- ... is about Ubuntu
It's probably okay. Or duplicate. Or something else. Honestly, who knows until we're looking at it.