We'll dive right in after the break and I'll tell you what I think.
First, lets talk about some things that I like. The first thing that I really like is the price! At the time of this writing the PDF will only cost you $2.49 US, which I think is a more than fair price for what you get. Second, I really like the fact that the special attacks and abilities provided aren't specifically designed for any particular class, and don't require any prerequisites other than proficiency with the weapon being used. I also really like that these rules don't favor any particular weapon type. With the exception of the quarter staff, each weapon is given exactly two special attacks or maneuvers. I can't tell you how delighted I am that this book isn't: "twenty new things you can do with a sword and five things you can do with an axe." That said though, the long sword ability, "Lock Blades," which allows you to make an attack roll as a reaction and parry a weapon attack (taking no damage) if you succeed, feels overpowered.
Of course I haven't actually play-tested any of these rules, but aside from Lock Blades most of the other abilities seem reasonable and none of them are too complex, taking only a few sentences each to describe. They allow you to do things like use your short sword to make a dazing attack with your pommel in lieu of doing damage, or pin a person to the wall with an arrow or dagger, or strike at and attempt to remove an opponents shield with your flail, or use your battleaxe to damage a target's armor. Many of these new actions require opponents to make various types of saving throws, in which case the "DC equals 8 + the attacker’s proficiency bonus + the attacker’s Strength or Dexterity modifier (attacker’s choice)."
The new weapons provided are cultural variations of existing weapons, with a couple having modifications or special rules that favor assassins and rogues. The flavor text helps make them unique to their specific campaign settings, but really the weapons themselves are generic enough that they could be inserted into any campaign setting if you wanted to give certain cultures or regions a few somewhat unique weapon options. The weapons have a mix of special maneuvers and attacks unique to them and some also allow you to use the special maneuvers and attacks given for their generic counterparts.
As far as disappointments, I'm a little confused as to why literally everything but the quarter staff gets two special abilities, while the quarter staff only grants the user the ability to "Vault," using their staff to perform a long jump that takes the character twice as far as he would otherwise jump. I feel like it would have been easy and made sense to allow the quarter staff to either "Trip" (like the halbred) or "Rebuff," (also like the halbred). If I used these rules I'd probably allow the quarter staff to do both of these things in addition to the Vault ability, making it the only weapon with three options instead of the only weapon with only one (non-combat) option.
But here is the thing: I probably wouldn't use these rules in most games that I played. Even though they are mostly balanced and not that complex, they do still add a layer of complexity to what is already the most complex part of an otherwise simple and elegant system of rules. Combat in Dungeons and Dragons already tends to bog the game down and the addition of these rules, no matter how simple they are, would still add more time to combat as players mulled over these new options and considered these new tactics. A few of the options, such as "Crushing Blow" and "Bloody Wound" also add some additional bookkeeping to combat, which can also slow the game down.
Of course, these drawbacks may not be drawbacks at all to you and your group, depending on your style of play and how crunchy you like your combat. If your group tends to like games with crunchier combat systems, or everyone likes the idea of having more tactical combat options at the expense of a little extra time and bookkeeping then these rules might be perfect for your group. In particular, if for some reason your group misses the added complexity of combat feats and feat chains from previous editions or other game systems then everyone will probably be okay with giving these rules a try. If you found yourself nodding your head to any of this then you should probably pick this up because, again, you can't really go wrong at this price point.
On the other hand, if you are dealing with new players who have little or no experience with Dungeons and Dragons or other role-playing games, or you feel like there are already plenty of options available and your combats already take long enough then maybe hold off on adding these options to your game, at least until everyone gets more familiar with their default combat options.