I went with the XCarve because it was an inexpensive way to get into CNC. The fact it was a DIY Kit kept the costs down a lot. When I built mine, I bought everything except the waste board. The waste board was nothing more than MDF and cost a ton to shop. So I made my own waste board. It was fun and relatively easy to build. However, since I built one, I'm not too sure how excited I am to build another one. There were a couple of things in the instructions that weren't correct, but I figured it out.
Here's a video I did about building my CNC. It's more about my experience rather than step by step tutorial.
You can use the XCarve software on the Inventables website. it's called Easel and super easy to use. It basically does 2d carving and also some V-Carving. Their website has a great community and a ton of projects, too. The Ventric sofware is super expensive, so I didn't buy that. But it would be a good way to do 3d stuff with a nice interface and use of 3d clipart. I don't do much 3d stuff, but I am starting to dabble in it. You can use Fusion 360 for free. It has a seriously steep learning curve, though. But I"m slowly learning it. But it will do all of the CAM stuff you need to do 3d stuff and design your own stuff. Then you can use Universal GCode sender to send commands to your CNC.