High Level Options, as can be expected, is designed to appeal to the player who has a god-complex. Oddly, however, the book is split evenly between a very useful discourse on good DMing and some bells and whistles for characters of 15th level and higher.
The first half of the book should have been part of the reprinted Dungeon Master's guide. While TSR has a tendancy to publish fairly uncreative and "hack-and-slash" style adventures, the suggestions and guidelines here are wonderful, a good review for an experienced DM and a great primer for an amateur DM.
The second half of the book leaves a bit to be desired. I'm not a fan of "high level" campaigns, but the information presented here has some rather obvious flaws. In many ways, the 10th level spells are disappointing in effect. They aren't more ingenious than 9th level spells, nor are they particularly effective. Likewise, the material presented for additional class abilities is too little, too late, in my opinion. These abilities do little to make a more formidable character.
All in all, the book is best thought of as a supplement for the DMG.