Should a router on a machining center perform the same tasks as a CNC router? Are the differences between the two primarily in the part holding methods? Is there a big difference in software and controller between the two? Can nesting only be accomplished on a CNC router? Are pre cut cabinet parts better processed on a PTP? Are oddly shaped parts better processed on a router? Could a router with a tool changer machine parts like a PTP? Which machine type can do what operations faster?
In general (and there are exceptions), a CNC Router is a much simpler, more reliable machine than a PTP (I can hear the PTP guys howling already). In a parallel head router configuration you also have the opportunity to work with multiple spindles in the material. The trade off is usually longer changeover time for the router, less machining flexibility (fewer tools available), poor performance on boring operations (slow), and less intuitive programming.
Point-to-point machines are vastly more complicated, more prone to bugs, and do a wonderful job on panel parts such as kitchen cabinets. These machines are usually run without fixtures, have a "Swiss Army" tool selection on board, and set up more quickly than routers. The programming software is usually very easy to learn and use if you are making common panel parts, but can be too "helpful" if you are trying to take more basic control of the machine. Many of the router spindles on the PTPs are just as good as those on the routers, and it is common to see the PTPs doing heavy profiling, and doing it well.
If I were running around the clock making nested upholstery parts from plywood, I would own a parallel spindle router. If I were making European cabinets, I would own a Point-to-Point. For business in the middle, (and most is) you will need to do some analysis and figure out which way you lean.