I've used VRBO for a non-disney trip once and it was fine. I use homeaway more often though (and my family booked 3 condos for our upcoming disney trip through homeaway). There are some "scam" listings on these sites, so you do have to be careful, but I've pretty much stopped using hotels since starting to use these types of sites a few years ago... it is SOOOOOO much nicer to stay in a real place, with a washer and dryer! and you get a lot more space for the money (my sister and I and our ton of boys usually travel together, so clothes washer is a HUGE plus).
I've found prices to be a little lower on homeaway - most condos are listed on vrbo, homeaway and airbnb, and the same place can be cheaper on one of those sites, so it's always worth it to check all three (also check for reviews for the same place on the other sites). The most important thing is to not make any payments through any means that would not be somehow refundable (ie: western union) As long as you use a credit card or paypal to make your payments, you can always refute the charges if things go south.
Also, contrary to what you might think - since the prices are all set by different people, better places can sometimes be had for lower prices in the same condo - so if you're looking for a 3 bedroom in Reunion for example, you might just find a 5 bedroom that's nicer and cheaper... so don't put maximums when you search.
Final advice - the farther in advance the better your rates are going to be and unlike hotels, the rates for a particular place will probably stay steady unless it's unrented a few weeks out (and then it may or may not drop) but you are almost always going to get the best deal by booking extremely far in advance (when all the best / cheapest properties are still available)