We use a  wireless system 802.11b/g system in our factory with no problems. We have 4 computers hooked up with one directly on the factory floor and one in our wire edm room.  

802.11 Wireless provides an additional layer that you do not have with a cordless phone or radio.  Namely, interference and noise is handled in an active way that guarantees delivery.  A cordless phone or radio is just transmitting blindly to a receiver.  In addition, 802.11 uses spread spectrum technology so that in-band interference only disrupts a portion of the signal.
 
Are there cases where too much interference kills the connection?  Sure, but there are ways to overcome most of them (Higher gain antennas on the access point, relocation of the PC, etc.)
 
We have an access point in each of two buildings.  We have excellent connectivity from everywhere that we use our laptops.