Ian Piumarta <ian.piumarta at inria.fr> wrote that:
    [performant i]s a perfectly good french adjective, and means precisely...
	
	> "[something] performs well, has good performance" and is therefore
	> "performant".
	
	...that.  If it isn't part of English, it should be.  (Who do we
	petition?  L'Académie anglaise ?? ;-)
	
I like to count syllables.
I note that "more performant" is four syllables, "faster" is two.
The problem is that "performs well, has good performance" is seriously
ambiguous.  For cars, for example, we can say unambiguously:
    X accelerates faster than Y.
    X uses less fuel than Y.
    X is quieter than Y.
    X uses less oil than Y.
    X has more leg-room than Y.
    X emits fewer particles than Y.
    X costs less than Y to buy.
    X costs less than Y to run.
    X smells nicer than Y.
    X pulls more birds than Y.  (Sorry about the dated idiom.)
    ...
But what does 'performs better' mean?

With respect to computer software,
    X is faster than Y.
    X is faster than Y for large problems.
    X uses less memory than Y.
    X is more accurate than Y.
    X passes more tests than Y.
    X is cheaper than Y.
    ...
are all aspects of performance.  If someone tells me 'X is more
performant than Y', then even with the French dictionary in front of
me I know nothing more than this:  the speaker approves of X.  I do
not know *why*.

In computing discussions, let us prefer *specific* terms to words
and phrases like "performant" and "performs well".