They're different and the easy things and difficult things are different. Which is the most difficult? For me it changes from day to day depending on what I'm doing and what I'm working on. Today it was Viennese Waltz that was difficult - so few steps and so few ways to make them look sublime! Fleckerls, fleckerls and more fleckerls! Next week we're working on Rumba so Latin will be harder next week (Rumba walks - it'll be more like Rumba marathons, I bet).
For me personally, I have heard that Standard is harder, yet I feel I am picking up Standard with much more speed than I ever did with Latin.
However, like an early poster said, I feel the more I learn in Standard the less I know! Recently I've been just practicing a Natural Turn. I always thought 'no biggie, no difficulty in just doing a little box with some rotation.' Pft! What a fool I am! I thought I knew how to do a NT, turns out, I still got a lot of work to do!
With Latin though, I feel like I continually look like a goon when I do it! On the other hand, I do spend a lot more time practicing St than I do Latin....
I guess my opinion then is something like this: both disciplines are difficult for their own respective reasons.
One thing they both have in common though: beautiful women and handsome men!
Well, last time I was going to Blackpool, they included Timothy Howson and Joanne Bolton, who won that dance, and Alan and Donna Shingler.
"Basics" is generally defined as "syllabus figures for the dance". My own definition in this case is slightly stricter in that I wouldn't include syllabus foxtrot figures with syncopated timings; without that additional restriction, there might have been one or two more couples in the final doing only basics.
I have had a lot of discussion with various professionals & students and still do not have a straight answer. Is there one? or is it just personal preference? I am looking in terms of technique, characterisation and rhythm here.
I think that question needs more context. If you are talking about competition, the style with the most competitors will be the hardest to win. Because if one is easier to learn at the beginning, the competition will raise the level of technique to the limits of what people can do, anyway.
Ballroom is harder because there's always this partner in my way. Latin is harder because I have to do things with less (or sometimes no) physical connection with my partner. Ballroom is harder because I have to move smoothly across my feet. Latin is harder because I have to be centered over my feet. Ballroom is harder because it's so structured, it's hard to let go and be expressive. Latin is harder because I feel silly performing sensuality.
You haven't gotten a straight answer, because there isn't one that's true for everyone. Though there may be one for a particular individual, depending on their body type, previous experience, and personality.