"Better" depends on what you want to do. SQL back isn't really complimentary to
stsadm - the overlap is almost 100% and the only real difference is the storage
space required.

FrontPage (or smigrate):
Pros:
- Can backup  single sites
- Can restore to another site  URL or server
- Can be done from a remote client
Cons:
- Doesn't store user or security information

stsadm:
Pros:
- Full fidelity backup
Cons:
- Can only be run on the server
- Can only backup a full site collection
- Limited ability to restore to a location other than the original

SQL Backup:
Pros:
- Full fidelity backup
- Can use incremental backups to save on storage space
Cons:
- Can only restore to EXACTLY the same location