I don't have an Aircable so I can't comment on it personally, but a lot of people have had success with it.
Really, the choice boils down to whether you want to use another CF device at the same time (you might want to use your CF microdrive) and whether you can put up with a device sticking out of the serial port some distance while net surfing/emailing. I also would not advise keeping the Aircable in the serial port with your Zaurus in your pocket/bag/whatever so you would have to keep unplugging it.
The Bluetooth standard isn't going change any time soon. They are working on Bluetooth 2, but that is still some time off especially in commercial products. The current Bluetooth spec allows for ~742Kb/s downstream in asynchronous mode (and you really can get that), so it will cope with many 3G services.
Dut does that men the limitations of the port will keep the aircable from getting anymore than 100-150Kbs?
In nother words, does CF max out currently at 700+kbs and the AirCable at 150+Kbs
Aircable' siteAirCable Technical Specifications (or would these better on a C860's port)
* Embedded Bluetooth 1.1, class 2 compliant software
* Radio Carrier frequency: 2.4 ~ 2.483 GHz, 79 channels
* Data Rate: 115200 bps
* Radio Performance Receiver: -85 dBm sensitivity
* Transmitter Power at Antenna port: As per Class II - 10 meters range
* Antenna: Integrated PCB antenna
* Dimensions 56 x 31x 11 mm
* Weight: 7g AIRcable Zaurus module
* Operating temperature 0C ~ +65C
* System support: Sharp Zaurus SL5x00 and C7x0
* Power consumption max: 5mA (no data), 20mA (at 115200 bps)
* Implements and supports Bluetooth profiles: SPP, DUN and LAN.