Giggs was world class. In his teens and early to mid 20's, he was one of the top 5-10 wingers in the world. However, you have to look at the context of his ability at the time. English football in the early 90s was pretty sh*t, particularly in comparison to Serie A, which was the leading league at the time. The game was still recovering from the Hysel ban; the best players had left the league and there was a lot of semi-alcoholic cloggers playing on ploughed fields fueled by fish suppers.
In that company, Giggs looked imperious. He was so much quicker with the ball at his feet than anyone else in the league and would just breeze by defenders and leave them choking on dust. Until the likes of Bergkamp and Zola arrived (and Shearer, Keane and the rest of the class of 92 emerged), Giggs, Cantona and Schmeichel were the only players in the division that were genuinely top drawer. It's hard to understand if you didn't witness it first hand just how much of a gulf there was between them and the rest. Sadly for Giggs, he suffered from persistent hamstring injuries through his mid-20s and that gradually eroded his pace. By his late 20s, he looked finished but then, and massively to his credit, he reinvented himself a central player and became more of a number 10. For a good while he was our only player who could thread a through-ball; we desperately needed a veteran Giggs against Palace.
Would be interesting to see him come through today, as the traditional, flying winger is something of the past. I imagine he'd be more of an inside forward or inverted winger; probably playing a similar role to someone like Sterling or Sane at City.