I only saw the Korean version "Playful kiss" and the Japanese "Mischievous Kiss" and "Mischievous Kiss 2" 

Do you recommend other versions? Why?

For me, the first taiwanese version, It startet with a kiss and they kiss again are the best of all but a bit older. After, my favorite is the japanese version i think it's because ofr this two version we see their married life and i love it!!! I also like all the other version: the new taiwanese , miss in kiss , i've seen the chinses too and the first korean movie. It's my favorite story 

There is also the 2015 Thai version called Kiss Me starring Mike and Aom. It was surprisingly good.

Actually, I know about all of the remakes and the source materials. I have watched all of them as well as read the manga. I thought some were better than others. I only mentioned the Thai version because I did not see it in the previous response.

I would recommend to wath the first taiwanese version: It started with a kiss and the sequel They Kiss again. This version has two seasons, which followed the whole story from their high school years till their working years. Ariel Lindoes a pretty good job with her character, making you empathize with her splendidly.Joe Cheng perfectly fits the cold, genius character. He does it so well that sometimes you really want to smack some sense into him. Many loved Ariel and Joe’s drama couple, and they even made other dramas together due to people wishing to see them together again. And also the Japanese version Itazura na Kiss - Love in Tokyo. With two seasons and one special, this remake was way better than the original version. Like the Taiwanese version, it followed the complete story. This version is a little lighter than the Taiwanese version and there aren’t as many crying scenes for the leading lady.

A Love So Beautiful

Very similar. FL loves the smart ML first and slowly melts the ML's heart. The characters are all cute and the acting is very good as well. For sure one of my favorite dramas ever!