Reply to Arpeggiator

Can anyone explain/have any tips on how to mimic alesso's arpeggiation in this song, starts around 1:10.

I'm using logic so I can use the arpeggiator in the 'environment' and I also have sylenth1 which has a built in arpeggiator, which one would you guys recommend for ease of use etc.?

http://www.youtube.com/watch?v=rcaQ_yO-S6E