Can't really say if it's the best romance. They're all so wonderfully different (at least the ones I played, I tried not to totally spoiler me) and - ashaming truth be told - I'm quite blind on the Cullen-eye.
Yes, dwarven female limits options and was / is a lot of fun with Bull. The toughest love, by all means 
The Cullen romance gave me all the feels. I recommend giving it a try. Personally, I like both his and Solas's romances equally. I haven't gotten around to trying the others, though.
I already posted this video I made earlier, but for the sake of the feels:
I will try it out eventually. My grand scheme is to do a PT for all the different romances. They're all such good characters
But I gotta say, having just completed Wicked Eyes and Wicked Hearts, and the way Morrigan half-smiled at Harold afterwards, when they talked about her joining the inquisition... for a moment I thought that if she were a romance option, I would drop everyone else and pursue her. That voice *sigh*
Of course, that was until Cassandra danced with Harold, and said, with a cute smile of her own, "This isn't exactly... terrible." 
Wicked Eyes and Wicked Hearts was both fun and frustrating. No matter how much I love the rest of the quest, I will never like that sequence that begins with going into the servant's quarters and ends with a dance with Florianne. The dance part is fine, but navigating that garden/courtyard/maze of rooms, trying to find the assassin in the clown mask is cruel. I do not like it. I also don't like needing halla statues to open doors, but it is what it is.
I didn't have enough statues to get into the royal vault and find the locket that would reconcile Celene and Briala -- which was my original intention, so... the Inquisition plotted a new course. Plans change. We must adapt. Now Gaspard is the new Emperor of Orlais, and apparently Blackwall -- who was nowhere near the Winter Palace -- absolutely hates the idea. 
Wow, that was quite a different ending than my first game. I'm gonna miss having Florianne as Skyhold's court jester this time around. Now for the next dilemma: Who gets to be the next divine. Was Cassandra in my first game, and this time Harold loves her, so I'm really gonna push for Leliana, but we'll see what happens.
Quote of the night (from Dorian): Did you see what that Marquis is wearing? That suit is a greater crime than anything we're looking for.