Just want to post my 2 cents here...
First You get out of it, what you put into it.... First Golder Rule.... I am in the cabinetry business... and I hear people all the time complaining about how something is not up to par... but how the work they want me to do is a piece of cake.... One thing I learned is good things take time...
In building a machine or kit... not only your experience and knowledge is critical... but also the complexity of the other components you want to implement.
My first CNC is mostly wood based, with metal rails/vbearings/and other parts... I am a meticulous son of a gun... but the fussiness and time I put in step by step to make each part as fine tunned as I can, is only an investment... It makes the work I produce with the machine only that much more accurate and precise....
The Original Poster sounds disappointed because he sounds like he want's to "bang it out" and have results without paying his dues...
Patience is not only required for the machine...but then will come the software, and experience, and learning from mistakes....