Nymphadora:
I have not watched any of Sung Joon's dramas, would you recommend this one as a starter?
Hmmm. Yes and no. I Need Romance 3 is by far my favourite role for him (and totally different from the other roles I've seen him in), but if you watch that first then you're starting with the best.
His character in Ms. Perfect was pretty great, although he doesn't get any kissing scenes (a tragedy). His character in Madame Antoine is frustrating, but if you can get past that there are some very enjoyable moments. He plays the second lead in Gu Family Book, so that's definitely not a must watch. His character in High Society is quite reserved, but you get to see SJ in lots of suits. (Also if you like Park Hyung Shik, his role in High Society is my favourite - the second couple outshines the leads for most of the drama). I haven't seen his other dramas yet.
I'd say try Madame Antoine first. If the frustrating parts don't put you off, stick with that and then watch Ms. Perfect, and then I Need Romance 3. Then you get to go from frustrating character with good moments --> good character with lots of growth but no kisses --> wonderful character with lots of great moments.
And so I don't feel like I've gone too far off topic in this thread, two kiss scenes from Bromance: