I use ##TODO in my code to mark places for future refinement or edge case handling. For example, I might use a linear search to get an algorithm working for testing. If all goes well, then I will probably replace it with whatever is most suitable based on real metrics. Same with edge-cases, I might think of one, but haven't yet written the test nor reasoned about it.

In my experience Debian is as good as Ubuntu (which is based on it) and in some cases better. The real difference is that Ubuntu is a bit easier to get going if you not experienced with Linux. If you have limited Linux experience, then you might be better off dipping your toes in the water with Ubuntu. Otherwise, read up and give Debian a spin. Since both are free, your only investment is your time and you will certainly learn either way. As far as development goes, I would dare suggest that Debian might actually have a slight edge over Ubuntu. Of course YMMV !