I only buy refurbished Dell business workstations. I will have had this one for 2 years, come April and haven't had a single problem. It was under $200. The only thing I would do different, is to spend a few hundred dollars more and get a machine with at least 32 or 64Gb of RAM. With my current 8Gb of RAM, Reaper starts bogging down when I have added FX. I will soon be adding additional RAM, to bring me up to this machine's max of 32Gb.
Do you really need to take your computer anywhere with you? By putting a PC on your editing desk and running cables to your booth, your environment will be quieter than having a laptop in there with you. Any cheap LED TV should work as your in booth monitor.