When considering purchasing a CNC Vertical Machining Center, some factors to consider include:

1. The types of materials that will be machined and the required tolerances.
2. The size and weight of the parts to be machined.
3. The number of axes that are required for the machining process.
4. The capacity and power of the spindle.
5. The size of the machining center and its suitability for the available space.
6. The availability and cost of tooling and cutting tools.
7. The ease of programming and operation of the machine.
8. The reputation and service network of the manufacturer.
9. The current automation and features of machine in the market you are looking for.
10. The overall cost and return on investment.

It is important to have clear and specific needs before making a purchasing decision. It would be helpful to have a professional assessor before making a purchase, so that, you can evaluate the machine before making a final decision.