It depends on what you want a CNC to do right out of the box. I haven't done any cuts with it yet so I can't speak to it's live performance just yet, but I can give you opinions of the build and overall quality of the machine.
I bought the mechanical kit which didn't include any electronics. It comes with everything you need to build a working X-Y-Z axis framework and you add your own steppers, controller, power supply, wiring, etc... They also have a full version that includes NEMA17 motors and an Arduino based controller. Just add your own spindle. I chose to go with the mechanical only kit because I added some upgrades right from the start including 4-axis NEMA 23 260oz-in stepper kit from Probotix, ACME thread for the Z-Axis, and added a drive shaft in place of the dual Y motors. It's a very configurable machine and easy to modify to fit your needs.
The makerslide setup and v-wheels are a nice design for the linear movement. It makes expansion extremely easy. If you want a bigger CNC, just bolt on more makerslides and you've doubled your size. The tedious part was having to tap your own holes for assembly. It's not hard, just time consuming during the build. But it helps keep their cost down and allows them to sell the slides in various kits beyond the ShapeOko.
Out of the box, the usable footprint is kinda small. About 11" x 11" of cutting space in any one operation but as mentioned above, if you just add more makerslides, you increase your size with little effort. The full footprint is about 20" x 21" in stock form.
The new version comes with double X axis for the gantry which seems to be pretty stiff and open ended frame so you can work long pieces in multiple steps without having to worry if it will fit in the machine. I also like the moving gantry design over a moving table because it stays within it's footprint so you know exactly how much space to dedicate to it which is great if you're in a small shop environment.
The belt system is actually very smooth and very fast. I'm still running it through its paces by running programs without the spindle running so I can get the belts stretched tight and get everything nice and square and ready for real cuts.
I chose a DeWalt 660 for the spindle motor for now. It's loud and I have to rely on an external router speed control to slow it down when necessary, but it was cheap and reliable place to start. Eventually I'll pick up a dedicated spindle that is quieter and can be speed controlled by the CNC controller.
Once I do some actual cuts, I'll post more along with some video.
As for the software, I purchased a CAD program so I could do 3D but if you only want 2D, you can get by with something like Inkscape or any other vector image program and then use either a free CAM software for your tool paths or purchase a dedicated CAM package. Once I get my 4th rotary axis up and running, I'll have to dump about $300 to get a CAM package that can do rotary tool pathing, but for now I'm getting by with 2d and 2.5d testing.