Nothing wrong with that suggestion at all, but they're a MC (Management Company), so you're going to pay more for the same place!
The beauty of the websites mentioned above is you're getting
owner direct pricing. MCs typically take anywhere from 10%-50% of the rental income from the owners, therefore charge a higher rate. Some guests are more comfortable dealing with a larger company for sure, but bottom line is you're going to be in the same homes! Some MCs won't even let you pick the specific home, they'll just tell you it's Windsor Hills and a 3 bedroom, for instance (I don't know if Global does this or not).
Why pay more for the same thing?