Thinking about getting the game when it comes down to about 20 dollars in price or 40 with the season pass. I like open world games. My favorite games this gen are GTA5 and The Witcher 3. Will i like fallout 4?

Judging from your tastes, i think you'll enjoy Fallout 4. Its got a nice and atmospheric open world, and is simply fun to play though :)

I find Fallout / The Elder Scrolls games really hit and miss. It either absorbs me and I play it for 12 hours straight or I get bored within the first few hours and never play it again. Fallout 3 and Skyrim are some of my favourite games of last gen, but I couldn't stand Oblivion or Fallout: New Vegas.

Fallout 4 is somewhere in the middle for me at the moment. Some sessions I really enjoy, some I don't.

I'd say you'd enjoy it, especially if it's your first Fallout.