As Parka notes, the DMP release of Flamboyant differs from the original Japanese. Not often that the western version actually gets more for their money, but that is what is the case here. What we get is five illustrations not in the Japanese edition (which also means five "blank" pages). It's good to see a western company put in some effort when they do release an artbook, as these tend to be few and far between nowadays, so they make it worthwhile.
The liking of art styles are subject to taste, but I like Ugetsu's work. I was only fully aware of it when I watched Burst Angel. If you liked the Burst Angel anime, then you'll like this collection as about half the book is devoted to it. You'll also find his linework for Burst Angel here as well.
There are two fold-outs in the front as well as a treat, so the art isn't just fitted onto a page which means we get to see more detail.
I only gave this a 4/5 because the range of his works in Flamboyant is too limited. I am aware he has done more design work which is why this collection disappointed me a little. What is in the collection is fantastic, no doubt about it, but I had just hoped for more of his other works to be included.
This is labeled with a "Parental advisory" sticker citing "explicit content", which is perhaps something that people buying this as a gift may want to be aware of. There are four or five illustrations which I would place in this category, and these are nudes. (The tone of these illustrations aren't sexual if anyone is worried about that, but this will depend on your own view of such things.) If I was to be more critical about this issue, perhaps one of these may be seen as more suggestive and verging on sexual. (Maybe.)