There is some useful documentation about using "create index" and gathering statistics on minor attributes of an index at: http://infocenter.sybase.com/help/topic/com.sybase.infocenter.dc00641.1570100/doc/html/car1347305833682.html
Now, none of that is currently available in 15.7 for the reorg command, BUT I seem to remember from the ISUG-TECH conference a few weeks back that Jeff Tallman mentioned that this (collecting column stats for minor key attributes) is coming for reorg in 16.0 (SP02?).
Which one is faster? Well, my _guess_ is that the drop/create index process is faster (or can be made to be faster -- sorted_data options, parallel non-clustered creation, etc). However, you miss out on some of the other work that reorg does and some of it's features such as online availability, restart, etc.
Give the documentation a good read on both fronts and let us know your results.