"Premature optimization is the root of all evil" -- Donald Knuth, 1974
Pretty damn good
Fast enough
Certainly one of the most memory efficient, tree-based APIs; possibly the most memory efficient
1.1 is 2-4 times faster and somewhat smaller than 1.0. An iceberg API was essential in allowing optimizations to be made while mantaining backwards compatibility
There are tradeoffs between memory and speed.