I don't have hard data but I do have a few tips. It would help to know what application you are using this for and why you prefer a CF GPS. Will it be in continuous use or be turned off.

You probably already know that the CF GPS will use power from the PDA, while the Bluetooth GPS will have its own battery. The PDA will use some battery power to communicate over bluetooth, but presumably not as much as the CF GPS. Most bluetooth receivers have 10-16 hours of active use, and a week or so on standby. 

I would tend to reccommend the latest bluetooth Rikaline GPS - I have an earlier one. Most bluetooth GPS will turn off (or back to standby mode) when the PDA does. Rikaline will also turn itself back on. Check the link to the right to check out some GPS receivers.

You will want to keep in mind what happens when a device is depowered. I have a compact flash GPS that will start from scratch whenever it is turned on, and a cold start might take two minutes. My bluetooth GPS will remember enough to get restarted in 20 seconds or so. This may or may not be the case with the devices you have.

Bluetooth GPS works better with an otterbox, but CF GPS will usually do fine in softshell dry bags. Bluetooth is easier to put at the top of a backpack for greaer reception, so your application matters.