The performance depends on which performance measure u r taking..
If we consider complexity as number of comparisions , then insertion sort works better than selection sort provided array is nearly sorted.
But if we consider complexity in terms of swaps or memory writes , then no doubt selection sort is better than insertion sort as selection sort takes O(n) swaps in any case but insertion sort may take O(n2) if array is not nearly sorted..
I hope u have got the point here..