I don't qualify as any part of an expert historian, but I do read a bit of it. I have read other of Erickson's side by side (as it were) with other authors works covering the same era. Erickson, as best as I can tell, is solid.
That said, her prose, while more than adequate, is not as riveting as Doris Kearns Goodwin; hardly a huge complaint.
This book was, for me, fascinating. First, all the nonsense about George III that I was taught in grade school was set straight. Americans are fed as much propaganda as the Soviets ever were. (That comment is not based on this book alone; just bolstered by it.)Second, I had a good bit of the politics filled in which made a bit more sense of my college 18th Century Literature class from ever so many years ago. Finally, the author takes us into the ninteenth century including a good bit of background on Lord Byron. Erickson leads us through the swing from what might be called libertine-ism into the religious mania that resulted in the Victorian (double) standards of behavior.
Very good stuff.