tl;dr version: Franchise is good.
Play the first two games at least.
- First game would be a masterpiece if not for some rather poorly implemented dueling, stealth and platforming sections that are merely decent on the rare occasions they work properly, and infuriating at all other times. Still an amazing western _*experience_*, with a sincerity in tone and atmosphere.
- **Bound in Blood** was a much tighter _*game_*, and the narrative is a lot more focused. They also got rid of most of the frustrating mechanics from the first game, however the "adventure" aspect suffers for it. Still amazing, but feels a little more like a cowboy shooter then a western _*experience_* then the first game. Wish they had made those parts actually _*work_* properly instead of scrapping them entirely.
Also, the dueling mechanic is **the worst** in the series. It can suck cocks in Hell.
- I have mixed feelings about **Gunslinger**, on the plus side the shooting is easily the best in the series and the dueling system as been given some _*essential_* anti-frustration features so that you can be better informed of what you're doing. That being said it's a **Call of Juarez** game in name alone, all effort to create an authentic western tale has been completely abandoned in favour of an arcade shooter with a cartoony, tongue in cheek vibe.
If you appreciate the more satirical and deconstructionist approach to the western genre then more power to you. I just felt like it was mocking the very aspect that made the franchise so compelling to me in the first place. Play it if you don't mind the drastic change in tone and want a solid western FPS with skill progression.