Can't really say anything about the SQL Dev tools from Microsoft or RefGate as I have only, to a limited extent, used SSDT from Microsoft.
Release Management though is something else. Good tool with lots of potential and use it daily. Got more than 70 release templates set up and use it daily to deploy quite a few apps with it. There are however some short comings of which Microsoft is addressing with the 2015 release. When this will be released to TFS on-premise I have no idea, but in private preview on VSO.
Release Management does make my life a lot easier because the automation it brings a long is super. Would like to automate it a bit more and add more approval layers, but that is apparently being addressed in vNext (2015). Also, it is highly irritating that you can't make use of if statements in the XAML workflow in the tool, but these things should also be addressed in vNext - No XAML though.