A 'hole' is a missing electron. If a hole flows, it will be in the conventional, or positive direction. However, a hole isn't something tangible - it's something missing. In order for a hole to move, an electron has to fill the hole from somewhere else, and thus it's still electron flow. After all, a vacuum cleaner doesn't suck, it simply moves air in such a way as to cause atmospheric pressure to move air in a desired direction.
Having said all that, as an engineer I have always used conventional current. I had to change, as my college classes required it. It's never caused a problem, and I automatically think in terms of conventional current. That allows me to analyze and design with PNP or NPN for instance.
About the only time it feels right to work with electron flow is when analyzing the inner workings of a vacuum tube. Which way does current flow in a voltage regulator tube or a neon bulb?