I got this for the GM DAY sale... A complete steal for 240+ pages of well-know, well-loved material from various sources on one of the most enthralling settings and subgenres to ever appear on written form.
MARS works as very good d20 setting, as the system is fine-tuned to fit the overall atmosphere and feel of the subject matter, and even if you--like me--don't like/use the d20 system that much, the information presented here in a cohesive, entertaining and concise form, will let your imagination roam free and fuel your gaming sessions, and make for a great role playing experience.
MARS is a self-contained game. Every single thing you need to run a game is right here, for you to work with it. So yes, many of the skills and feats are here, again, but localized--where needed-- to the world you are about to enter. That means you don't need additional books to play or refer to while creating characters or running the game.
Then if you, like me, just can't refrain from adding a few thing to it, as it's d20 you can easily port your evil Illithids here to add to the mix of opponents the players' heroes will face over the course of their adventures in this beautiful, dying world setting.
Do yourselves a favour: Buy it. Especially if it is avialable at a sale price.
Adamant Entertainment has yet to dissapoint me with one of their releases, and quite frankly MARS is one of the best they've put out.
LIKED: The presentation, the quantity and quality of the information and it's adaptation to the d20 system.
DISLIKED: The relatively few illustrations. For such a grandiose setting and the sheer amount of source material, this could have had a few more of them pics!
QUALITY: Very, very good.
VALUE: A veritable steal taking into account the quality/price ratio!
SATISFACTION: Extremely satisfied.