Twenty ten or Twenty eleven as base for responsive child theme

Question

I'm about to make a new child theme and really would like to learn a bit about making it responsive. The design/changes will be rather small.

I've done some child themes for both Twenty ten and Twenty eleven but not sure which one to choose for trying to learn responsive design. You could argue Twenty eleven is the latest but I've read somewhere Twenty ten is better maintained.

I know there are many barebones/frameworks, but these two I know quite well.

Any thoughts on this?