You might also like to take a look at Lingua::EN::Inflect, which has a more highly configurable numbers-to-words converter than either of the two modules you mentioned.

For example Lingua::EN::Inflect:

• supports decimals
• ignores intranumeral punctuation
• allows alternative groupings of digits (to correct pronounce phone numbers, IP addresses, etc.)
• allows alternative pronunciations of 'zero', 'point', and 'and'
• understands ordinals

One reason not to choose it is that it currently doesn't handle numbers bigger than ninety-nine decillion, nine hundred and ninety-nine nonillion, nine hundred and ninety-nine octillion, nine hundred and ninety-nine septillion, nine hundred and ninety-nine sextillion, nine hundred and ninety-nine quintillion, nine hundred and ninety-nine quadrillion, nine hundred and ninety-nine trillion, nine hundred and ninety-nine billion, nine hundred and ninety-nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine (i.e. 999,999,999,999,999,999,999,999,999,999,999,999)

The next release (due RSN) will handle numbers of any size, using the extensible notation described by Conway (no relation) and Guy in The Book of Numbers.