I prefer SN to jumping for a few reasons.
One: less difficult to "bite the bullet". Jumping from a building is just more scary than drinking poison, imo.
Two: Easier for me to understand. When jumping from buildings or bridges, you have to calculate at what height you'll die. Water vs concrete, what position you'll be in when you'll land (I've seen people say "when you jump, aim--" NO! I will not fucking aim after jumping off a building!), etc. And you can get really high up there, but even at towering distances there's a chance of survival. I do not want to be one of the unlucky ones who ends up paralyzed and mangled.
Three: Bystanders won't have to watch and won't be able to intervene. This is assuming I'm doing SN method in a sufficiently private place and took the meto. I remember one person took SN without meto or any other preparation and she ended up vomiting so loudly that the neighbors called 911.
Four: Less sensational for those who live. I imagine me dying from SN will be easier for others to get over than me jumping. Also, I want my suicide to look calculated so people will be less likely to exaggerate how unreasonable I was being (they still will). Don't get me wrong: a lot goes into ensuring an effective jump, but we're talking about optics here. SN will look more thought out.
