After the runaway success of Fifty Shades of Grey the mainstream romance genre has become extremely bogged down with BDSM options hoping to cash in on that trend, most of which are poor quality. It can be tricky for the sincere ones to shine out. So this, first off, is the loveliest, sweetest, and most thoughtful BDSM romance that you're likely to come across for a good long while.
The most notable plot difference from other BDSM stories here is that the dominant is significantly younger and less experienced in sex (and life!) than the submissive. There are other stories that do this flip, but most simply present it ham-handedly and essentially require you to just ignore that core power imbalance to make it work. This works completely within the ages through, and you never forget for a minute anyone's real age.
This is also very decidedly a romance book and not a work of erotica - relationships of many types are the focus of the story, and sex takes its place as part of a human relationship, not aside from it. The sex is placed decidedly inside the mental aspects of BDSM, the exchanges of power, and the carefulness of it. If you've read and enjoyed Hall's other books and are hesitant about BDSM content, push forward, he completely works it.
A unique book from a very unique voice in the gay romance genre.