Setting: Insanely detailed (look at www.tekumel.com
if you don't believe me.) You have very complex clan-based society providing for lots of intrigue. The setting feels like a fantasy (albeit non-Western) even though it is actually far in the future. You have sword and sorcery however there is also highly advanced technology lost in the world, this provides for exploration and dungeon crawl. The setting is human-centered, but there are quite a few non-humans race that range from interresting to bizarre. Deities are very important in the setting, as is personal and clan honor. It is truly unique so it hard to compare it to anything else, but if I had to I'd say picture the clan/honor structure of L5R + the science fantasy of Thundarr the Barbarian + a vibe of Vance's Dying Sun + a healthy dose of Mayan/Aztec/Indian flavor and you might get something like Tekumel.
The Book: Very pretty, nice layout, it comes with a great big poster map. The information contained is very nicely layed out and flows well. Lots of little sidebars and organziation that helps you understand the world's vibe. For example the non-humans have both a Stereotypes and The Reality sections for background. There is a lot of background in the book.
The System: Derived from Guardians of Order Tri-stat system that is used for BESM and SAS. The system seems a little more crunchy than typical Tri-stat, which in this case is a good thing. It is point-based character creation with six attributes (Str, Dex, Intelligence, Psyche, Charisma , Willpower), with the option to buy other nifty things (like Ambidextrous or a Aptitude with a skill) and a skill sytem. It's roll under (on a d10) a target number determined by Attr+Stat. There is a neat system for special items that could be used to really have customized equipment. (The fact the setting reflects personal status through possesions makes this a very nice thing.) I'd say the system is more complex than BESM but slightly less complex than d20. The setting is integrated into the character creation, such that as you build your character you pick up some setting info. In fact, the first two steps of character creation are pick your clan and pick your deity. Also the system suggests many optional rules, and different campaign levels (from gritter to heroic, from low to high status) are built in the system.
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The closest connection this game has to BESM is a green triangle on the back with Tri Stat Derived around it. Anyone that realizes this connection to BESM knows too much about the system already to make fun of you.
If you are looking you any of the following you may want to check out Tekumel...
fantasy with technology in a non-contrived way
something with potential for intrigue
if the word "post-technological" gives you goose-bumps
if you think Mayan/Aztec/Egyptian/Chinese/Japanese/Indian cultures are cool