I'd say right now it's statistically insignificant in their differences. The one area, maybe, is decision making, maybe. You've got to frame every comment about Allen last year by reminding people just how poor the o-line play was, and how deficient we were in skilled offensive positions. All that has changed now, so Allen will not need to play "hero" ball. Thus, this year will be a much better indicator of his mental processing.
As for him versus Darnold, I'd say it's a draw after one season, both have areas to improve upon, and both had some highlight reel things as well.