Sometimes rules supplements read like the world-setting bible of frustrated novelists. While solid world- building is a useful skill, you don't always need four paragraphs of flavor text to tell you swords are cool, magic is power, shadows are scary, and orcs are savage. Sometimes a GM doesn't have time to slog through a page of history for every magic weapon. Sometimes all that's needed are a few cool ideas, with just enough information to use them in a game. Sometimes, all you need are bullet points.
Bullet Points are a line of very short, cheap PDFs each of which gives the bare bones of a set of related options. It may be five spells, six feats, eight magic weapon special abilities, or any other short set of related rules we can cram into about a page. Short and simple, these PDFs are for GMs and players who know how to integrate new ideas into their campaigns without any hand-holding, and just need fresh ideas and the rules to support them. No in-character fiction setting the game world. No charts and tables. No sidebars of explanations and optional rules. Just one sentence of explanation for the High Concept of the PDF, then bullet points.
The High Concept: Seven feats designed to augment the options and utility of war masters (from The Genius Guide to the War Master) or, if war masters aren’t being used in a campaign, that can be taken by classes that receive bonus combat or teamwork feats as class features (using their class levels as war master levels for prerequisites) or characters that have the Leadership feat (using their character level as war master levels for prerequisites). This is the latest in a series of products to celebrate the "Summer of Bullets" event!
The feats included are:
Advance In Ranks (Combat): You can direct allies to move together, guarding and watching over each other.
Formation Fighting (Combat): You can direct a tight formation of melee combatants to fight together, aiding them all.
Mixed Order (Combat): You can direct allies around you to fight in a specific style, emulating your weapons.
Overwatch (Combat): You can watch out for moments when your allies are distracted and warn them about potential attacks.
Set To Receive (Combat): You can prepare troops to use reach weapons to great effect against advancing foes.
Tactical Commands (Combat): Your deep understanding of the flow of combat allows to you give allies new combat options.
War Signals (Combat): You have mastered a set of signs and code words to give orders quickly and easily.
A cavalier has some ability to augment his allies with teamwork feats and (at least in some cases) abilities from his order, but the majority of his abilities focus on his own combat expertise and dealing horrendous damage to single foes.
The War Master (written earlier, so I could help what little overlap there is) is a unit commander, who has a suite of abilities (similar in game mechanical function to bardic performances) that augment all in allies in a broad set of situations. The War master is designed to allow someone with only a basic grasp of tactics give his side a big, ongoing tactical advantage (without overlapping with the bard).
As it happens the feats in #1 With a Bullet Point: 7 War Master Feats are useful for anyone who wants to do more tactical augmentation and group buffing. They are built so if you don't use the war master class in your campaign, you can instead give these to any class that has bonus combat feats, bonus teamwork feats, or the Leadership feat.
So while they augment the war master's abilities really well, they can augment the group effectiveness granted by a tactically-minded cavalier, fighter, inquisitor, or sorcerer with Leadership as well.
DungeonmasterCal, for me, the difference is that the warmaster is the class I go to to be inspired by really cool and interesting methods of buffing your allies, and the cavalier is who I go to to hit things hard while mounted :)
War Master is a really cool class, and I'm quite fond of their eye for quality ability (the one that enhances masterwork bonuses).
The War Master is a party buffer who can hold his own in combat, thanks to his high BAB and that eye for quality ability. He won't be touching anywhere near the fighter, but he does fine.
The cavalier is a warrior who has some party buffing abilities (that are actually a bit more limited than most people think, I believe, since they can only grant feats gained through Tactician)