I’ve just been getting started with it, but I like it very much. You may also want to take a look at PicSender, which has some nice features as well. Roger, I believe is the developer’s name, is very receptive to comments and suggestions. The program is nice that you can create common shapes on the fly, and macros are pretty easy to add (or combine) in the case of uninterrupted probing for X, Y, and Z axis. I know there is some functionality to program certain keys to do certain things. There is also a visualizer, which is not real time, but it does give you some idea of how the G code is going to be carried out.
I also like the fact when you first load up a G code it tells you the maximum X, Y, and Z travel. This is a very nice feature in my opinion. Sometimes I forget to allow enough clearance for Z travel, (or have too much), which will trigger limit switches. I can fix things before I get started. It also tells me roughly how much room is being taken up on the table.
Lastly, there is also a real-time update of total time left based on feed speed. You can also update speed on the fly. PicSender has this feature as well. It’s nice to slow things down (or speed up) based on how the cutting is going, without having to generate new G code.
Overall, I like the look and layout, and it has not crashed as of yet. More than I can say for Universal G-code sender.