I'm not sure on the knew 4.51 version. But I am using EMC2 with my Taig CNC and it really is amazing. The system is freaking Free and you can run your cnc system, are you kidding me??? I love EMC2, it's so easy setting everything up, specifying what you have and so on. I just love everything about EMC2 and being a user, I can tell you that you should Mill with EMC2. It's very user friendly and just love all it features. I love that it shows your piece being cut and all the depths that it will cut and everything.
I can't get over how great it is.