We've been using the MakerGear M2 for a couple years and it's pretty amazing that it's STILL getting really good reviews! I noticed 3D Hubs users agreed and so do people on Amazon. Even though it's single extruder without tons of bells and whistles, it just prints and prints and prints! That just goes to show you don't have to be MakerBot or Pettit to make a solid product!
I need to take a closer look at that PrinterBot Simple Metal. It's getting so many good reviews lately.