This pdf is 26 pages long, 1 page front cover, 1 page editorial, 1 page SRD and 1 page back cover, leaving 22 pages of content for the new steeds and stallions, so let's check them out!
After 3 pages of short story introducing us to the matter at hand, we are presented with more complex rules for horses - from feeding horses (grazing vs. hay and supplemental food) to stabling horses in different kinds of stables. We also get horse-quality templates ranging from nag over broken-down to average and high-spirited as well as charger. Even cooler, we get rather detailed tables of quirks for horses to give them personality beyond the standard, from sudden stops, to biting steeds, we get several quirks and associated value modifiers. Included is also a special kind of horse disease and new rules to govern horse races.
While the templates are nice to have and add versatility to the horses, these new rules (introducing relative speed and stamina) are simple, easy to use on the fly and make for a cool additional usage for horses beyond the obvious means of transportation. In fact, a running battle on horseback could easily be pulled off via them. Speed is Str-mod+ Dex-mod+1d6+quality modifier, Stamina is Con-modx2+1d6+quality modifier. Players can use up to 3 points of stamina per round to boost speed. The GM rolls an open d6. Players roll one per point of stamina used and for each die equal to or above the DM's result, they get +2 speed for one round. Each rolled result equal or below the GM's result takes one point of stamina away from the horse for that race. Simple, fun, cool.
Editing and formatting are top-notch, I didn't notice any glitches. the pdf features the classic 2-column layout and used parchment-look of NNW, along some neat pieces of stock artwork. The pdf comes with extensive bookmarks as well as a printer-friendly b/w-version. I really, really liked this pdf - the templates to horses make steeds more complex, the quirks grant them more personality and, especially when combined with 4 Wind Fantasy Gaming's plethora of statblocks from Phantasia Zoologica, make sure that no two horses are the same. The additional race-rules make for a great and easy way to add them to your game, even on the fly. It is here, however, where the one major gripe with this pdf lies - It's too short. It would have been rather easy to add e.g. chariots/carriages etc. to said rules or at least give advice on how to handle races with them. The lack of said rules makes the pdf fall a bit short of absolute excellence. My final verdict, though, will still be 4 stars and a definite recommendation to buy, especially at this low price-point.