If time is an issue, then look for something that supports differential backup.
The initial backup will take the normal amount of time, but, after that, the differential backups will be pretty quick.
If time isn't an issue, you can pretty much use anything, but, remember to TEST the backup, since I have had cases where the backup image was actually corrupted, but the *container* was OK. When you select verify in backup products, they don't actually verify the data, they just verify the container is OK, nothing else, which I think is lame.