I watched this drama for Hyun Bin, Ha Ji Won, Lee Jong Suk, and Kim Sung-Oh.
I am a huge fan of those four that I just named.

I've seen 4 to five of their movies/dramas. Wonderful acting.
Since I love them so much, I watch any drama with them in it. Whether they're villains, whether they have a cameo... whatever. I'll watch it for them.

Secret Garden is indeed a wonderful drama. I laughed throughout the entire show. I cried a tad bit later on, but it wasn't for long.
I suggest that the one's who haven't seen it, please watch. This is the only drama I'd proudly recommend. All 10 stars!!