Justin has hit claws dug into the urban side of pop. 1D is fluff/dance pop that likely wont hit the US big before it they fizzle out and return to the UK.
The 1D guys aren't insanely attractive like Justin Bieber, but their music is catchy.
They are slowly getting an American following.
But to answer the question, I believe they will be side by side with Bieber.
They also have Big Time Rush to compete with.
And the Justin Bieber-Jonas Brothers comparison is laughable at best. Justin has accomplished 100x what the Jonas Brothers have ever and will ever, even if he can be an arrogant prick.