I wasn't aware that Horizon and Halo don't count anymore.
Tough break for MS really as their big games not counting really hurts them!
The math is pretty easy for me - take what I spend a month vs the games I play and would have actually bought. Back4Blood, Forza and Halo would have been no-brainer buys for me so that's $180 already and that doesn't count the bunch of other games I've played. I'm still on that cheap deal we got ages ago so I don't even know what I paid per month but it is super cheap and easily well worth it. Game Pass also gives me Destiny 2 on Xbox for now too.