Alternative questions to the Net Promoter Score or better metrics of User Experience

There are some very detailed discussions about the validity of the NPS. But the take home message is that you can't really improve what you can't measure effectively, so it is still important to come up with metrics (preferably from a number of different sources).

One of the key recommendations is to change the question from whether you would recommend the product to something else. I was wondering whether anyone has tried this and what the result was?

UPDATE: Since I first asked this question many years ago, there have been more recent articles talking about the gaps in the NPS score and how other metrics can be used to fill in this like the Customer Effort Score and how it compares to the NPS score.

Are there more recent studies or research to support a more holistic measure of customer experience?