I don't know if this innovative or not, maybe everyone does this. But I use something I call a protein efficiency rating ("PER")- its a formulla which basically tells me "how many calories am I forced to consume in order to get each gram of protein that food provides?" The lower the rating, the more efficient the source.
So for example,
MetRX RTD (100 cal., 21 g of protein) = PER of 4.76 (100/21)
Low Fat Cottage Cheese (180 cal., 26 g of protein) = PER of 6.92 (180/26)
When you take the calories of a typical protein bar (typically 250?) and divide by the grams of protein (around 20g), you get a PER of 12.5
That tells me it's not an efficient protein source. Now granted, in certain cases, you have reasons for consuming an inefficient protein source (e.g., need to spike insulin after a workout, need to consume fiber, vitamins, antioxidents, etc.). Other than protein however, the protein bar offers very little other benefit or reason to consume it (except as noted above, sheer convenience).