I don’t know if there is an easy way to answer this, haha! I go to VIXX events here in Korea (I currently live in Seoul) and it’s hard to gauge who is the most popular. The cafe has grown SO MUCH in the past month (literally, over 1,000 new members). Leo’s Birthday event registration was filled much faster than Hongbin, but his event was announced further in advance and the cafe has grown since then so that would be unfair. Because of the age group that likes VIXX in Korea (there’s a lot of 14-17 year olds), Hyuk is really popular as well because of his age. N and Ravi and Ken are very popular too, though! Honestly at every event I’ve been too, they all get about equal amounts of cheering! If another admin has a better answer, let me know. I see a lot of Ken and Ravi signs, though. Still, I think they’re all well loved.
As for international, I have no idea. But a lot of people seem to like Leo and Ravi!
I got to see VIXX at KCON last month so I can only judge from the reactions I saw there. During the fansign and Q&A session, there was about an equal amount of screaming for each member as well, but out of all the VIXX fans I got to talk to, they were somehow all Leo-biased (myself included, lol). Ravi also received a lot of cheers when he said, “Wassup L.A.!!!” Like Admin 4 said, it’s actually hard to rank them in terms of popularity because I feel like everyone loves all the members enough to show equal reactions. Dunno if that makes sense, but yeah… ^^