In the past few years it's become commonplace to shit on gen 1 because of its bugs and other flaws, and from what I can see those games have become somewhat of a joke in the Pokemon community, at least among younger players.
Let me get this straight: gen 1 is far from perfect, but in spite of all its flaws it was still a (very) fun experience, and yes, it still holds up today. I find myself replaying Red or Blue every 4-5 years and I'd choose them over the past 3 generations any time.