Yeah I'm running the game at 1080p and just tried it with HDR and it just looks kinda dull. Kinda darker and less colorful.
EDIT: I messed with some settings and now I think I got it dialed in. It looks really good as far as contrast. There isn't good contrast on SDR. Or at least not as good. I think the darkish tint is coming from the shadows cast over the field in some spots.
This was actually in a day game. I just started a night game and it doesn't look all that great. I don't know. Maybe it's just me. Seems like the colors are more vibrant in SDR in night games.
As far as input lag, seems to be fine for both hitting and pitching. But like I said I'm playing in 1080p so you said that should be 15ms right?