I've used Republic for about a year now, and have been quite happy with the service. Started on the (painful to use) Defy XT, and now enjoying a Moto X with the $10/month Talk+Text plan. I was happy to find a carrier that does not require you to purchase an overpriced data plan to simply use a smart phone on the network. I have WiFi saturating me all day long, so I don't need to pay for Cellular Data.
Republic does have company customer support via a ticket support system, and live chat. Republic only uses VOIP for WIFI calls, when WiFi is not available, native cellular voice calling is used. I do agree though, that with the current increasing competition and other good options, I would not even consider using the $45 LTE plan on Republic. There’s some push for them to offer some more compelling LTE options.