What kind of projects do you expect to be working on while you finish up school? Do you usually design more 3D parts than you do 2D (or tubing)?
Hard to weigh in without totally understanding what you want to create for your projects, but for prototypes of mechanical systems, I would think a router would be a good way to go. As we've seen before, you can cut out your own plate sprockets and such, and cutting chips on the router would still be faster than waiting for something to print (usually). Also, don't forget about being able to prototype in plastics and wood! I think the decision also depends on what machine at your school's machine shop is usually more readily available.
Personally, I love FDM printers and have used printed parts on many occasions, and the kids on 11 got to use a few critical printed parts on this year's robot as well. I think our parts were all printed on a Dimension 1200, but I don't recall exactly. The ABS, when printed correctly with the correct parameters, was really great for my applications as well as 11's (gears, spacers, couplers, collars, dog-bone linkage on 11, sensor mounts, etc). Nothing was in high load, just parts that we didn't have time to have sent out for conventional machining, or it was a bit too complex to machine easily.
Just a thought - if you do end up with a CNC router, I would think that modifying a bed and adding a 3D printing head would be a decently easy project for when you have some free time. You could, in the long run, make a hybrid machine with swappable heads, no? Or is that a silly idea? Probably a silly idea
