I use some precuts in a lot of my quilts, I like to buy charms and jelly rolls every now and then because they often have some fabrics in them that I wouldn't normally go out and buy if left to my own devices. That gives me a nice challenge. I don't think I've ever used just a single charm pack or single jelly roll or fat quarter collection when making a quilt. Instead I use them along with whatever else in my stash looks like it would work for whatever project I'm working on. My most recent quilt top is a jacob's ladder that's in process and it was made using jelly roll strips from 3 or 4 different jelly rolls for the medium and medium darks along with some leftover Paula Nadlestern patternista fabric for the darks and a no name light fabric that I purchased off ebay years ago to back a quilt.
Don't think that just because the companies and shops advertise the compatibility of all the fabrics within a single collection that that means you can't mix and match from a variety of collections.