I go through phases with SMS and calling. Sometimes I think it’s more effective to text, because that gives the other person time to finish doing what’s important and call me later. That’s when I’m in the "phone calling is interuptive" frame of mind. Other times I feel a call is much more efficient than 10-20 words in a text. That tends to merge with my Scottish ‘healthy regard for the bottom line’ (i.e. getting wound up paying 12 pence a text when that would buy a few mins airtime).
Sarah Bradshaw, business reporter of the Pughkeepsie Journal (apparently New York’s oldest newspaper!) has more defined views on the subject of calling vs texting.
Read and sympathise with her 30-something plight: Here