Here are the results of multimap vs multiset (using same test case as above)
Here are the results so far (in ticks):
10,000 loops
10 sprites
[map] average: 234
234
234
234
[set] average : 254
312
234
218
100 sprites
[map] average : 2755
2844
2734
2688
[set] average : 2668
2047
2500
3459
1000 sprites
[map] average : 34,568
34,813
34,297
34,594
[set] average : 32,291
32,390
32,375
32,109
10000
multimap) 388,969
multiset) 388,563
Its pretty damn close.