So, it's clearly that STS is a bigger hit worldwide, so we should only discuss about their success in US. Which one you think the most successful single in US. Here are some statistics:

US peak:
Side To Side #4 (so far)
Good For You #5
Same Old Love #5

US sales:
STS 526k (hasn't finished its chart run and still #5 combined on itunes)
Same Old Love 1,3 million (estimate)
Good For You 1,5 million (estimate)

But we should also consider that sales have drop 40% since 2015.

Streaming

US views on YT:
STS: 93 million (still increase more than 8 million views per week)
GFY: 92 million
SOL: 64 milliom

US spotify:
STS: 62,3 million (still top 10 on Spotify)
GFY: 91,5 million
SOL: 74,7 million

SOL wasn't that big of hit.

Insert YouTube stats and Side to Side will end up being bigger than the others!

atm SOL seems bigger, but STS will be bigger after its run

For now, GFY>STS>SOL

Side to Side will be the bigger hit at the end of the day

GFY>SOL>STS
At the end of their runs, I think STS won't outsell either but with streams will be bigger.

STS by far. It's streaming numbers destroy all Selena singles and I think it'll have better longevity.

Side to Side, the song that is successful in the USA but also worldwide. Not everyone has that.

I'm saying SOL > STS > GFY

It feels like: Same Old Love > Good For You > Side to Side.

I guess its STS judging by the stats though

Side to Side feels the biggest.

WW Side to Side EASILY, the others were local

US Side to Side too

STS

Poll's up, girls!

Edited: i've just added YT views

Side to Side>those other 2

the next few weeks when STS hits no.2, it will all become clear.

Side To Side, clearly.

In what sense exactly? GFY's WW peaks might not have been the highest but it had *longevity* which kept its sales alive, it didn't go top 20 in the UK & still managed to sell 400k there despite Selena being a total flop there. It sold 1.5M in the U.S. and 2.7M WW not to mention it did so well in the states in sales, radio & billbord all on its own, it didn't have a single televised performance and managed to go top 5 while other singles need countless promo slots including a high profile award show and a discount in it's run to chart inside the top 10, it's terrible low budget music video that was an apple exclusive for a month and has no replay value whatsoever didn't even have the original track in it nor did it even feature ASAP yet it still managed to somehow garner over 300M views on YouTube.

Clearly GFY > STS = SOL

s2s