Which of the following is considered better style?

$ie.text_field(args[0], 
$test_data[args[1].to_s]["#{args[2]}_fld"]).value=$test_data[args[1].to_s][args[2].to_s]

$ie.text_field(args[0], 
$test_data["#{args[1]}"]["#{args[2]}_fld"]).value=$test_data["#{args[1]}"]["#{args[2]}"]

ie is it better to use args[1].to_s or "#{args[1]}"

My current thinking is that "#{}" should be used when concatenating 
strings together with values (or interpolating), where as .to_s should 
be used when you want the string representation of an object.

Thanks
Kev

PS - I managed to get rid of all the evals hooray for me!