They only get a little more from ads, subs are still around 50-50(subs with prime gives like 30 cents more) that has also been discussed before on twitch forums when the affiliates got the option to get money from ads, basically the tiny line between those 2 is smaller, now the difference is about having transcoding always enabled and 3 slots for animated emotes.Pretty sure partners always have better deals than 50/50 on twitch, that's common knowledge.