Whereas the wired ones upload their backups at full gigabit speed (~100MB/s including overhead), the wireless ones only ever upload at ~10MB/s. I might see it go up to ~30MB/s if I'm lucky, but we're talking pigs flying over blue moons.
The wireless machines range from "one wall away" to "other side of the bloody house", but they're all the same. Even if I get one one sitting right next to the router it won't do more than ~10MB/s. I'm also located in the middle of nowhere in terms of EMI, so the air is clear.
Wireless is bullshit. If you need speed, just run copper and save yourself the grief. You only use wireless when the convenience of not running copper and/or being mobile trumps the lack of speed and reliability.
