I tend to hire off Freelancer. I haven't seen too much difference in people found. It seems more in the way of how you filter people as there is a bunch of poor performers.

I find Upwork seems to give people high summary ratings and when you look at their history and there is a bunch of bad reviews. There is something dodgy going on there which is a main reason I flipped to Freelancer. That and I thought it was good to support a company from my country.