The most common reason (I see) for going to such a solution is that existing solution is seen as slow or too resource hungry. If that is the case, then you might want to consider moving to block change tracking, which can make database backups incredibly fast.

Veem wont change anything about your archive logs - they still need to backed up no matter what. So with block change tracking, you might find you might not get any real benefit from a non-RMAN solution.

With any 3rd party solution, the most important things are:

1) you have a cast iron guarantee from the vendor that *they* are liable if you *cannot* restore. If they state they support Oracle database, they better be prepared to put their money where their mouth is

2) it is going to be upgrade compatible. Nothing is more frustrating than being stuck on a version of the database because some external component won't work with the latest version

3) you have familiarity and expertise with the product

And of course...testing. It's like the old quote:

"A backup without a test of the restore is not a backup...it's just a file"