I really suggest a gigabit switch; its just going to keep latency and overall bandwidth restrictions to a minimum.
Latency difference will be minimal (hundred usec at most) and unless he will have some future use with those switches, it's not worth it (if he can have 10/100 for less price).
If the switch has an uplink port or some sort of high speed link ability to another device, you would use that to set up a one wire link to the shed as well.
Pretty sure if OP asking this question he isn't going to have SFP/infiniband uplink.