I found the quick window to be useful enough to buy the quick circle case....especially the qi charging one. Yeah it's expensive but I have to keep this phone for like.....ever.
I find that keeping my phone in pocket with a regular case, it registers button presses when I get a call and using BT. With the QW case on my G2, that ended. Plus, if I got a call I could answer it without opening the case and all the sweat from my face didn't all over the screen.
I wish they had qi charging backs readily available. I know....ebay...but I don't use a CC. I only use debit, and my debit card won't let me purchase anything out of the country. So this is my setup......USB qi charging receiver from Amazon ($12), Spigen gunmetal slim armor case ($16), and a Spigen 0.2mm tempered glass SP ($26). For now it's a great setup and works for me till I get the QC case.