GFYG is slick and fun!
It's a Class/Level game, not a skill based game. It's clearly based on the Castles & Crusades SIEGE engine, an OGL version of the d20 system so it's very easy to pick up if you're familiar with any d20 game. (aside: I highly recommend C&C. Check out the Free QuickStart rules).
The 'rules light' game design is simple yet robust with no skills or feats, so character creation and action adjudication is qick and straightforward. It's easily adaptable to any situation the players may get themselves into so it's easy to run as the Game Master.
What makes it FUN is that the default answer is "Yes" if the players want to try something, not "no, you don't have the right power/feat/skill/proficiency." Of course, characters of a particular class perform the skills associated with a class better (like a gunslinger using sneak/stealth will never move truly silently, as a scout doing so would).
Those seeking a rule for each and every possibility will not find them, and to me, this is a strength of the game. The GM is encouraged to use common sense and communication with the players to adjudicate unusual circumstances on the fly to better maintain the narrative flow of the story and keep the game’s pace up. In short, rules lawyers need not apply, and everyone will have more fun.
(The above paragraphs are also true of Castles & Crusades, BTW.)
The classes in GFYG are cleverly designed and fit well the mold of popular Wild West fiction. It's easy to see a party of these characters meshing well and providing all the skills needed to succeed a mission.
The game comes with a good GM section, several references of real Wild West people from history and three scenarios the GM can expand into adventures (I love the A-Team reference in one of the scenarios, a great touch!).
The equipment section is purposely vague, and some players may want more details, but it totally works. It's a rules light game and arguing that a Winchester may do 1 hp more damage than a Colt would add nothing.
If I were to add anything, I'd like to see Beyond Belief publish a few adventures for GFYG, and perhaps publish a Weird West suppliment. But as is, I reckon GFYG is damn near flawless.
In summary, I'd say GFYG in fun and accessible. I say Go For GFYG now. I recommend it highly! (and for only three bucks, take a chance if you're on the fence)
A+, 5 out of 5 stars, a 10. :-)