> Quite means something different. In British "quite good" is similar to "particularly good"
Not really, it means something more like 'fairly' or 'reasonably' good.
Not really, it means something more like 'fairly' or 'reasonably' good.
And if you preface it with 'really', it doesn't mean you're not lying, it makes it more like 'bloody' good. (With possible implication that this was unexpected, again depending on intonation.)