I understand the desire to work with free software and recently I have been playing with Laserweb3 which is a free and opensource browser based application. It gives you more control then Benbox when it comes to speed and resolution and best of all it also works with GRBL.
One of the things they are building into it is the ability to do raster and vector in the same job. This is working for some firmwares but not GRBL currently but should soon.
The other cool thing is that it works with dxf, svg, png, jpg, bmp, tap, stl, and gcode files.
It lacks a lot of the cool features that BCL and T2Laser have and is by no means a replacement for them.