I personally go with Evelyn on most playthroughs. I like Azzy how she is and, while her scenes are pretty hot, I've always had a thing for Evelyn and I think the dragon transformation just boosts that. I wasn't too into it at first because a lot of Evelyn's scenes weren't there but they've been steadily added back in. Also, storywise, I like how Ashe's Lair isn't abandoned with Evelyn and that's also one less person crowding Hawkthorne. Evelyn talks of big conquest while Azzy mainly just wants her own hive with the PC and Lia (if they're dating) so I like the big picture concept.