Hiya, I'm the original author. tl;dr for those deciding whether or not to read it:

If you are thinking about build versus buy for your ETL solution, in this day and age, there are enough great tools out there where buy is almost always the right option. You may think you can write a "simple" little ETL script to solve your problem, but invariably it grows into a monster that will be a reliability liability and engineering time suck. The post goes into more depth on why that is. Enjoy!