I agree with x2, a bit of a vague question. However, I've worked on both products, and they each have their good and bad parts. I found Veritas Netbackup a bit easier to work with when it came to various operation systems. I was doing backups of oracle on solaris and sql server on NT/2000 with no problems, all from a solaris-based master server. Recoveries on veritas have tended to be faster than those in legato, but that is most likely due to the legato configuration here, which I'm not sure was set up properly to begin with. I did the setup of veritas from the ground up, so things were a bit cleaner.
Also, I am using an older version of legato (5.1), so I'm sure things have improved dramtically in the area of multi-OS support.
That's my two cents, anyway. Either product is a solid choice.
T