The two are pretty similarly sized, O'Brien is 6'2" and Strome is 6'3". That said, Strome had notable skating concerns that were known dating back to juniors. I think O'Brien could have similar issues, but his skating is more "not a strength" than "bad".
I also think what Strome has become (playmaking top-6 center without speed) is pretty reasonable to ping O'Brien's upside at, although I've seen scouting reports that suggest O'Brien also projects to be good defensively as well. Either way, Dylan Strome has turned out into a pretty damn good top-6 center, so I wouldn't be mad at all if O'Brien becomes a similar player.