I have an R2. I have just started using it. They use Cura to generate the gcode files by default, which is not nearly as nice as MatterControl. I am working to configure a profile in MatterControl to build gcode files for it.
The printer is designed to only be connected to by IP. So until MatterControl adds an IP connect, this will be manual file management, which is a shame.
Overall, the printer is very nice. I have had to add a support for the extruder cables, so that they do not drop down into the top of the printer and block head movement. Kind of amazing they did not find that in testing. The printer runs a full level before each print, which slows things down a bit for lots of small prints, but makes sure the alignment is right. The fact that the build plate is both heated and really easy to remove (the simplest I have tried) makes part removal a dream. And you can use an iPhone/iPad (and Android, I expect) app to monitor the print process (as long as you are on the same network), with 4 simple steps to connect to the printer.