First: Narrow down the category of machine that is appropriate. CNC Routers come in a wide variety of price points. Some brands are know for high speeds or extremely tight tolerances. Komo, Anderson, DMS, Northwood and C.R. Onsrud are some brand names that cater to high speed high tollerance applications. These brands tend to be more expensive and ore often overkill for most jobs.
How do you know what type of machine to target? There are two critical questions to ask yourself in this regard. First, how many hours a day will the machine be running? Most custom fabricators will run their equipment a just few hours a day. In this type of shop it doesn’t make much senst to pay an extra $80,000 for a machine that runs at 3000IPM rather then 1500IPM. Next: what is the tollerance requirement? If you are making aerospace parts out of expensive materials and your customer is measuring your finished product on a CMM machine you would be wise to puschase a high end moving table machine. The rule of thumb is that the difference between a machine that can achieve .02 tollerance and a machine that can achieve .01 tollerance is $100,000. If you are working looser tolerance requirements perhaps wood or another similar material that expands and contracts based on temperature and humidity, a lower cost moving gantry cnc router is probably the way to go.