Sometimes it recognizes what I've said correctly.
Sometimes it comes up with totally nonsensical interpretations, e.g. misses an initial consonant even when I emphasize it.
Sometimes it goes into a spin and says it can't recognize what I've said, when the recording sounds exactly like the prompt.
Sometimes the recording misses a group of words in the middle of a sentence.
Sometimes when I listen to what was recorded I get a buffer dump which includes words said in the previous response.
Most discouraging responses of all are
(1) when it appears to record what I say, but shows no "play" button so I can't listen,
(2) it refuses to respond in any way to a click on the microphone button, (
3) when it provides an error message as soon as the icon appears (when the icon hasn't been clicked) and
(4) when I can speak, voice recognition can recognize, but I CAN'T HEAR WHAT I SOUND LIKE. Nothing happens when I press the play button.
I have a late 2011 MacBook Pro running OS X Yosemite version 10.10. 5 (the latest). About Chrome tells me Chrome is up to date.