Primer Extension for RNA quantification

How accurate is primer extension with radio labeled primers for the quantification of RNA transcript?

Knowing that RNA is less than stable, I understand the reasoning for the conversion to cDNA, but wouldn't the extra steps involved in this process make it more likely for transcript degradation or loss to lead to an underestimation of yield?

Would it be more accurate to use a fluorescent RNA gfp mimic to allow for direct correlation of absorbance with RNA abundance?