I went with SRAM XOs also - shifting the front der with Shimano feels like its way too far. Plus I like being able to dial the front der in as I move through the cassette. Saves 150g too - extra bonus.
One reason upgraditis happens on the low end bikes is because they are equipped with such heavy parts. The stem, bars, seat, post, pedals - all really heavy. You can lose a pound and a half with some easy switch outs.