using U3 application

I have several usb drives, 8 gb cruzers, 16 gb ultras and 4 gb cruzers.  The 8 and 16 gig drives have secure access.  The 4 gig has a launchU3 application.  The U# application secures the drive and requires a password to login.  The SA provides a vault with login requied.  Is there any differences in the security supplied (not how it is implemented but how secure the drive is)?  

I prefer to have a password on the drive and then be able to access the drive.  I can access multuple drives concurrently that way.  Can I format the SA drives and load on U# to change how the drive perates?

the new drives with SA do not support U3 so you can’t just put U3 on them.

SA uses 256bit AES software encryption

U3 used 128bit AES hardware encryption

if my memory serves me correctly.