The 10 miles of solid rock kills ya at Mt. Whitney. The sand gets ya at Mt. Langley.
The yack trail out to either Army or New Army Trail rocks and rolls and sandy. Once you get to about 12,300', 1 trail become thirty routes to the summit. The steeper more direct ones are best.
I would take Army Pass, it more direct and it eliminates the 300' back to New Army Pass, which is a royal pain in the rear end. There are a couple small blocked sections near the top of Army Pass that are easy to navigate your way through.
