I can understand what you mean by cpu/mem bloat (I'll add to that install size, assuming this packages things up with all dependencies), but what do the other things mean?
For "usage", mono being like a kind of jvm, you will have a lot of "desktop graphical" or integration issues.
I can't swear that it will really be the case, but here are some examples of kind of thing that I expect:
- Icons, window decoration, style, not matching the system.
- Copy paste issues, for example the middle click not working.
For "dependencies", not considering the real dependencies, you will have to force your user to install mono and its own dependencies. As the application will run on this, in a similar way that you would have to install a JVM + classpath for Java apps. And this one is really fat an ugly.
For "cpu bloat", even if JIT can be more efficient on the long run, there is usually a higher cost at startup. For GUI application that you start often, like a calculator, that could be annoying.
For "ethics", the code will have to run on the mono(ie .net) kind of jvm and so you are dependent of this engine to run your code. And this engine, even if mono is the open source one, is controlled by Microsoft.
They control the language, they control the features, and it is not the spirit that built the linux community to rely on "base components" controlled by Microsoft.
It is a little bit like the control that Oracle has on Java even if not completely similar.
