In the average case for large datasets. Quicksort is O(n^2) worst-case (choosing the worst pivots possible), and Bubblesort is O(n) in the best case (e.g. an already-sorted array).
The C++ Bubblesort will have better worst-case and best-case performance, but worse average-case performance, for large inputs.
But this is all irrelevant, because in Python, you'll be using Timsort[1], which I'm pretty sure is implemented in C anyway. In C++, you'll be using std::sort unless you have a template allergy. If you use the Gnu stuff, that will be Introsort[2]; if MSVC, Quicksort.
The C++ Bubblesort will have better worst-case and best-case performance, but worse average-case performance, for large inputs.
But this is all irrelevant, because in Python, you'll be using Timsort[1], which I'm pretty sure is implemented in C anyway. In C++, you'll be using std::sort unless you have a template allergy. If you use the Gnu stuff, that will be Introsort[2]; if MSVC, Quicksort.
[1]http://en.wikipedia.org/wiki/Timsort [2]http://en.wikipedia.org/wiki/Introsort