I played 2, 3, and 1.
Suikoden 2 was a very "right place right time" kind of game when it released during my mid-teen mouse years. I was extremely engrossed in how unique and fresh it seemed, and the story between the main characters really emotionally hooked me.
I tried to replay it about a decade or so later, but it didn't go so well. By that point in my life, the mediocre (sometimes outright terrible) localization of the game was a lot more apparent. I found myself surprisingly disappointed.
I liked S3. It didn't quite grab me like S2 originally did, but it had enough good moments that I felt positive about it. I found Hugo and Chris to be a bit disinteresting at first, but I have grown to appreciate their characters a little more over time.
I can't remember much about Suikoden 1, despite that I played it last of these three.