My friend and I put many, many hours into Wildlands on co-op so we're currently playing this now that the Ghost Experience mode is out. It's decent enough, the problem being that it feels like there are too many systems at odds with each other and the balance isn't anywhere near right. With gear score off and some of the other elements turned down/off it becomes a reasonably tactical open-world shooter, but so far for us it seems far easier to get spotted inadvertently and end up in a horrendous firefight compared to Wildlands. The drones are frustrating, they don't add anything enjoyable to the game at all. Things like having to bandage wounds seem neat in practice but it takes far, far too long and results in you either being too wounded to move or unable to move while healing meaning you take even more damage and die. The controls feel very clunky and unresponsive at times too.
I have no real idea what it was like at launch beyond what I've seen/heard but there's still an awful lot of fixing and tweaking they need to do. By the end of it there'll be a reasonably decent game in there for co-op players. It's still no Wildlands though.