What I've witnessed is that my two rams get along perfectly fine with my angels, no feeding problems apart from that the rams tend to stay towards the bottom so you may have to hand-feed, apart from that angels tend to be aggressive towards other angels with the dominance factor and occasionally go for a nip of anything that gets too close (e.g. tetras). This is what I've witnessed though, don't take my advice strictly to heart, the situation in your tank may be different.