Summary
1) Splay trees have excellent locality properties. Frequently accessed items are easy to find. Infrequent items are out of way.
2) All splay tree operations take O(log n) time on average. Splay trees can be rigorously shown to run in O(log n) average time per operation, over any sequence of operations (assuming we start from an empty tree)
3) Splay trees are simpler compared to AVL and Red-Black Trees as no extra field is required in every tree node.
4) Unlike AVL tree, a splay tree can change even with read-only operations like search.
Insert Operation