Short answer: which is better for Shopify attribution?

It depends on what "Shopify attribution" actually means for your store. If you're running Shopify with Meta as your main ad channel and nothing else, Triple Whale was built for exactly that setup. If you're selling on Shopify plus Amazon, Walmart, or other marketplaces and need one place to see it all against your ad spend and GA4 funnels, that's Trivas's core use case.