Welbeck definitely has more pace. Iwobi is pretty quick in short bursts, though, like Rosicky. But yeah, taking on defenders 1v1 is definitely not his game.
@Luca_from_Italy no, I like him, I said this yesterday:
That said, I try to stay cautiously optimistic about him. We've seen a few young players, Ox among them, start fast, only to see the flaws in their game a bit later. We don't know what he looks like yet on bad form, or when he stops riding this wave, it stops being a dream come true and it starts becoming more a job. But yeah, I like him, he's got natural intelligence on the pitch, he very often does the right thing, he's got end product, and he looks useful on defence and in transitions. That's a good recipe for a very good modern wide player. I still feel Gnabry is the bigger talent between the two but Iwobi might just turn out to be the better player by virtue of being good but not great at everything and having a very good attitude and working for the team, and perhaps just having a better work ethic/professionalism in general.