Why not use Microsoft Backup

Okay I’ve been in IT for a few years, but in the last 2 years I’ve been the only IT guy in a small company. Every place I ever worked used the Vertias, the gold standard for Backup. I’m in a situation where I’d like to save a few bucks on a backup operation and I want to know why everyone seems to use 3rd party backup solutions. Is there a problem with the MS Server provided backup?

Thanks,

Seth