I'm shooting mainly AVCHD footage and my workflow involves making an img of the SD card first then letting FCPx ingest it - I transcode because I'm on a little 2012 mac mini.
I have also re-wrapped some 1080p60 footage with clipwrap (before i realized FCPx now handles this as of 10.0.4) and then ingested it via file import. I've seen some folks who use Cannon DSLRs etc (no AVCHD file structure) actually individually rename each file first (e.g. bob and sue.mov) then import the footage as a keyword collection.
So two different methods. Making an image of the SD card also sucks as you have to mount the image each time to see the contents and FCPx will copy the files to the events folder so now you have just doubled the space! But supposedly conversion / rewrap will remove the meta data - clip wrap has a way to preserve creation date so that's at least one plus. I've looked and my camera does not seem to really have much meta data (GH2, Gopo 2, TM700) so that would be one disadvantage. Using the file import has a downside as you can't skim and select footage but I don't seem to use this feature with the AVCHD footage anyway.
If you don't create an image of the card and mount it then you can't ingest it with the camera import method right?
So what is the best method - I'm leaning to the rewrap and then ingest and tag / add keyword method rather than my img creation method that takes up double the space on my HDs.
Generally speaking, I like to keep my original capture (P2 in my case) on a separate drive altogether. Then I save my project and event on another drive, often the system drive, and I import the footage. As that makes a folder storing footage, I add folders to that folder for things like SFX, Score, Foley, and so on, that I import using keywords. To me, it doesn't make sense to create folders as keywords and drag and drop and rewrap and blah blah blah because that's what X is very good at. There's even an S_Ton of 3rd party apps that let you get the media out of X and into a plethora of other apps.
/* make sure you select the preference so the media is copied to the event not just aliased. Then you can unmount~dismount, whatever's the right term, the original capture drive. You really really really don't want to lose that data. */
I hope that makes sense. The nomenclature is all wonky-mcgee compared with Legacy terms.