Simplicity and efficiency.
It looks simple, but it is not efficient way, copying the whole vector is costly operation (copy to temp and them copy it back). Instead a pointer based approach will be more efficient like this. (Note the changes are marked)

Qt Code: 
  1. #include <QDebug>
  2. #include <QVector>
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6.     const int inSize = 10;
  7.     const int outSize = 10;
  8.     QVector<QVector<int> *> vecToSort; //<<<<
  9.  
  10.     // Create Vectors
  11.     for(int i = 0; i < outSize; i++)
  12.     {
  13.         QVector<int> *vect = new QVector<int>(); //<<<<
  14.         for(int i = 0; i < inSize; i++)
  15.             vect->append(qrand()); //<<<<
  16.         vecToSort.append(vect);
  17.     }
  18.  
  19.     qDebug() << "Before:";
  20.     for(int i = 0; i < vecToSort.size(); i++)
  21.         qDebug() << *vecToSort.at(i); //<<<<
  22.  
  23.     // Sort Vectors
  24.     for(int i = 0; i < vecToSort.size(); i++)
  25.         for(int j = i; j < vecToSort.size(); j++)
  26.             if(vecToSort.at(i)->at(0) < vecToSort.at(j)->at(0)) //<<<<
  27.             {
  28.                 QVector<int> *tmp = vecToSort.at(i); //<<<<
  29.                 vecToSort[i] = vecToSort.at(j);
  30.                 vecToSort[j] = tmp;
  31.             }
  32.  
  33.     qDebug() << "After:";
  34.     for(int i = 0; i < vecToSort.size(); i++)
  35.         qDebug() << *vecToSort.at(i); //<<<<
  36.  
  37.     return 0;
  38. }
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