Definitely regular floss. The picks are good and pretty convenient, but the extra plastic that has to be thrown away is really bad for the environment.
I use regular floss but thats mostly personal preference, I feel like I can clean my teeth/gums better that way but I don't know if there's any actual difference.
Whatever you like and will use regularly. I use tape floss, a friend uses super thick floss. Whose is better? Technically, probably hers. However that thick floss is a hassle and hurts my fingers and teeth. Will I use it faithfully? Nope! So tape floss for me and my teeth are happier for it. “Perfection is the enemy of the good.”
Picks! I never understood how to use traditional floss, so the picks are the best. I also have braces and have to use special orthodontic ones.