I bought this while it was $20 and definitely was worth such price. It has its flaws but for such price you'll 100% get your money worth it.
This game's main problem is its main story missions. While the story and characters themselves are engaging, the main story missions are very, very linear and generic ones that don't try to do anything creative. You can't choose different routes or try any creative solutions for problem in them. If they want you to go full action in a mission they'll force you to by having a character doing stupid mistake to uncover you, and if they want you to go full stealth they'll force you to by forcing an instant game over on being exposed mechanic on you. You play these missions the way the developers want, which is very disappointing, especially because how long the story is. It's at least a 30 hours main campaign without side activities. A little more creativity in designing them would have a helped.
However, once you decide to stop doing main missions and explore the world you'll find a completely different game that encourages you to be creative and plan well for any side activity. Doing ambush camps are a lot of fun, thanks to different ways you can tackle them. It never ceases being fun to attract a nearby horde or group of freakers to the camp and let them clear the majority of it for you. You can go sniping from distance, you can go stealth, you can go full action, you can do anything you want. Clearing hordes requires a lot of planning and crafting, and rewards you for being smart with what you have. The open world is very organic and that's the best thing about it.
It's really shame they couldn't copy the same creativity to the main missions. Pretty weird when you think about it.
I rate this at 7/10 thanks to this unfortunately, but for 15-20 dollars, this is a great deal. You will enjoy your time with it and won't feel like you got robbed of your money or something.