G is backwards compatible to B but it reduces the speed of the network all across the board. If you want to take advantage of G, get all the machines on G. There are no drawbacks but you want to read up and implement a security policy so the neighbors don't pilfer your internet
- regardless of what flavor you run. The other thing to remember, is the higher speed of G will generally be higher thru the house than an all B network. So if a B network that starts at 11Mbps drops down to 4 Mbps after the signal goes 50 feet and thru some walls, a G starting at 54 might get you 8 or so in the same conditions.
The other thing to keep in mind is that if your sharing is primarily for Internet and you are capped at 1.5 D/L speed, a 54Mbps is no faster than 11Mbps.