would like to purchase a 3 axis benchtop machine with ,the 4th axis option. my buget is $7000 and I have bobcad V21. does anybody have recomendations.the machines main use would be for prototypying, materials such as steel and aluminum.I have a brigeport 9x42 table which I use to do much of my work.I also understand that there are several machine out there. flashcut ,microknectics,cnc masters to name a few.the question is which