If I'm making a donation quilt I don't mind using the "fix" stitch, but if I'm using totally different coloured thread top & bottom on a gift quilt, I leave thread ends & methodically hand tiey them, and thread them in through the batting every once in awhile. It takes time....but it's a neater look & I hate it when I see a "lump" of thread on the back of a quilt from doing the fix stitch.
So interesting how we all have our own preference......hope you find a way that suits you.