Funnily enough the first time I used foundry was as a player in a 5e game, and even though that's probably the weakest game integration on the whole platform it was still enough to convince me to buy it. Now I'm using it to run PF2e and it's phenomenal, I can't imagine anything else getting anywhere close in terms of QoL and useful automation.
I do wish it wasn't so reliant on third party developers though, while I love the amount of modules that are available it sucks that when a new foundry version releases you pretty much still need to wait until the modules update, if they even update at all. Some module's functionality should just be absorbed into the base system.
I played it a bunch during the public playtests throughout the past year and I think they have a fantastic base here and it genuinely feels more like Battlefield than anything DICE has put out in recent years. That being said the game is currently missing a number of QoL features, the menus are especially basic and feel like placeholders, and the audio design is extremely basic. I do expect those things to change throughout the early access period though and the game is great fun regardless