Making a part on hobby CNC miller

[JAZZCNC]

Also how easy would it be to replicate that drawing above, for me new user, or for anybody who knows what they are doing lol.

Well for a new user then probably bit of challenge but for someone used to Cad then no problem as you can see with the picture below which i've just knocked up in less than 15mins from your pics and obviously would have been quicker if I had dimensions to work from. Creating tool paths would be another 10-15mins.

Now obviously I'm quite experienced and using Solid works which is highend software and really this is the problem most new users have.? Software makes all the difference and having software that's taylored to the type of work your doing really helps. For instance ArtCam could be used to create the 3D toolpaths for this part but it's more woodworking based so the 3D toolpaths it provides will not be optimal. Where has Solid CAM which again is highend CAM software gives much more options regards 3D toolpaths.
Now both these programs are Highend in there own fields so it highlights why having software suited the type of parts your making will help. When you get to the lower end cheaper software you have Even less options regards 3D toolpaths so it becomes more important to find one that suits the type of work your doing.

Hope this helps.