Updating parent themes vs. updating starter theme

Question

Context:

I use framework parent themes (e.g. Thematic) mainly because it ensures that my custom themes inherit cutting-edge and standard compliant code.

Why I'm not yet using starter themes:

I'm reluctant to use starter themes (e.g. _s, Bones etc.) because, as I understand it, I'll need to screen for code changes with every version update and then manually apply them to my custom theme. I'd rather

My question:

Is my understanding of the process of updating starter themes correct and if so, is it not less work to simply reverse engineer a parent theme once and have automated version updates rather than repeatedly manually (and perhaps tediously) having to update my custom starter theme?