Vector.<> vs array
From the adobe documentation page:
As a result of its restrictions, a Vector has two primary benefits over an Array instance whose elements are all instances of a single class:
- Performance: array element access and iteration are much faster when using a Vector instance than when using an Array.
- Type safety: in strict mode the compiler can identify data type errors such as assigning a value of the incorrect data type to a Vector or expecting the wrong data type when reading a value from a Vector. Note, however, that when using the push() method or unshift() method to add values to a Vector, the arguments' data types are not checked at compile time but are checked at run time.
Pro: Vector is faster than Array - e.g. see this: Faster JPEG Encoding with Flash Player 10
Contra: Vector requires FP10, and according to http://riastats.com/ some 20% of users are still using FP9
Vectors are faster. Although for sequential iteration the fastest thing seems to be linked-lists.
Vectors can also be useful for bitmap operations (check out BitmapData.setVector, also BitmapData.lock and unlock).