I can't say I care for the notion that there is an opposition between the terms in the first place. Viewing these terms in opposition is a very modern phenomena, and it wasn't that long ago that the two were synonymous. Or rather, where the word "spiritual" is used today, "religious" would have been used not even a century ago. I still use the word "religion" in the old sense, though on occasion I might substitute the word "mystical," but never "spiritual." Folks have taken to putting a wedge between the two terms, with "religion" designating the organized/public practices or beliefs and "spirituality" designating personal practices or beliefs. All sorts of other assumptions and aspects get stuffed under those labels, many of which I find contentious for various reasons. In simple terms, I find it to be a terrible map of the territory that is a barrier to understanding, particularly the moment you step away from considering only a very narrow subset of religions.