Free VOIP Phone System For Small Biz: Don’t Buy It

I got an email today from a company offering a FREE Voip phone system for small businesses. It’s free and they display advertising advertising on your phone system. They are not selling to customers directly, but they sell to carriers who have the option to offer the service for free to customers.
My initial reaction is that you should not go for this. If you don’t have money and can’t afford a phone system use Skype – or another proven system. Why settle for advertising?
Getting a PHONE SYSTEM for “free” with advertising doesn’t sound so great a deal for your business, especially with something as important as a phone system.
I’m sure the company is just fine, but I don’t think the premise of the overall offering is good for small businesses.