@rhettinger
I completely agree with not creating a backward incompatibility at this point in time.

The real issue is that decimal.to_eng_string() was written to a (unfortunately chosen) proprietary specification which does not entirely correspond to the engineering notation.

A quick web search shows that a lot of people are in search of a *true* engineering notation implementation. In the phylosophy of "batteries included" it is a pity this useful and very common notation is currently missing in Python.

I would therefore suggest adding a decimal.to_true_eng_string() with the true engineering notation.

Hence, this bug could be reclassified as asuggestion for enhancement.