Tied for me. The first has much more enjoyable combat with far less glaring flaws to me but RDR 2 has way more nuance to its writing/characters, a superior open world, higher highs and much lower lows.
RDR1 is one of the greatest games ever, but there is nothing it does better than RDR2. All the flaws that RDR2 has, RDR1 has them worse. I say this having played both to completion in the past few months.
Arthur Morgan made RDR2 an incredible experience, the epilogue in particular made me a little weepy thinking on the consequences of his actions.
It's my GOTG so far, superb game that was superior to its predecessor in every way.
RDR2 is one of if not the greatest achievement in open world craftsmanship/design to date. It's rich, deep, surprising, thoughtful, while reaching levels of detail and immersion I've never seen. The story and character work are no slouch either, featuring a classic character in Arthur Morgan and enhancing the overarching lore of the Red Dead universe.
It is hands down one of the most fun games ever and the soundtrack being taken from popular spaghetti movies just screams nostalgia. Not to mention it has Red Harlow, Jack Swift and Annie Stoakes who are the most badass wild west characters ever.
I would say Red Dead Redemption comes really close because while the gameplay isn't as smooth as Revolver, it was still very good because it's arcade roots weren't forgotten.
The only good things Red Dead Redemption 2 has going for it is the Story, music, the map and the countless Easter eggs. Everything else sucks.
RDR because it's easier to just pick up and play yet big and beautiful enough to let you enjoy it for as long as you want. RDR2 may grow on me, I can feel it's a 'better game', but it just has too much going on (for me).