I think you should search this forum more. There was a lot of discussion about F1 and AOS....
This is just my opinion...
CP may be faster but I think that AOS is more secure (there was a lot of discussion on this topic also), because when you go back for the CP and if dont get your GC your F1 most likely will be cancelled, so you will not be able to come back, if you stay and do AOS and dont get GC there is a chance for you to stay on F1 status in the US...
if you work... be careful about working on your F1 while the AOS is pending...