Best dual WAN solution?

Hello, I was looking for a dual wan router mostly for “internet backup” than for load balancing. I have read some people reviews on the Xincom DPG502 and the Linksys RV016, the opinions are very divided though. Does anyone knows or are using some of this products? a similar ones? My most concern is the VoIP and the VPN that we use, apparently, a lot of load balancing routers does not like VoIP.

Thanks