Right now we're using a Labjack at the PC end, and parallel communication so basically one wire+ground to every sensor and output. This solution has been working trouble-free but the wiring is a complete mess.
We're using 3 CAT6 cables at the moment which is bad enough, we're adding more sensors now and would need a 4th one to have enough leads.
We figured it'd be much nicer to have all communication from and to the PC go through a single cable. We need the Arduino anyway to control the 16 7-segment displays we're adding as well, so I figured we might as well switch to some form of serial communication while we're at it.