Shoot both 50 Hz and 60 Hz HD, which camera w FCP?

Question

Hi again, Guys.
In a prior discussion I started, asking about a good modest priced HD camera that would output files that would work well with FCP, the consensus was that the Panasonic HMC-40 was a good choice at a modest price for shooting HD material that would be cut on FCP 7.  Sadly, I neglected to say, when I started the discussion, that ideally I need to shoot both in the US and the UK.  i.e. at 60 Hz and at 50 Hz respectively.   When I researched the Panasonic HMC-40 I was told that it could not switch between 60 and 50 Hz.  But that the next camera up COULD switch.  That camera is the AG HMC 151 E.  I was told this by a Panasonic rep in the UK.  But the problem is that I would like to puchase the camera in the US.  The US model is the AG HMC 150.  And that model it seems DOESN'T switch between 60 and 50 Hz. It only shoots 60.  (Why Panasonic has done this is a mystery to me.)
On a tech discussion group about HD shooting, one person said that the problem with shooting 60 Hz in the UK is mainly lighting, e.g. if you are shooting with florescent light in the UK, you might get flicker if you use a 60Hz camera in the UK.  So my questions are:
1) If I am shooting in the UK with a 60 Hz camera (i.e. a camera I have purchsed in the US that is not switchable) what are the biggest problems?
Is it only if I were shooting in florescent light, or is the quality overall a big problem.
2) If I shoot 60 Hz but am shooting in the UK, can I use FCP to convert the 60 Hz materail to 50 Hz and will that solve any image problems?
3) Now that I have mentioned that I would like to be able to shoot in the UK and US with the same camera, but that I want to buy the camera in the US, does anyone have another recommendation of a camera that is in the $2,000. range that would serve this purpose and still create files that would work well in FCP 7?
Do Sony or Canon address this switchable 60/50 Hz  issue more effectively than Panasonic?  In the earlier discussion, it was noted that Panasonic cameras created files that were easiest to use with FCP.
I am sure I have said things here that reveal how unknowledgeable I am about shooting HD.  But this will be my first camera purchase after having been an editor for over 10 years.  Any advice most welcome, and thanks in advance.

Answer 1

Thanks for this very helpful info.  In a separate discussion Shane did share that tutorial.  Obviously that is crucial.
Reading reviews of the XF100 recently, I saw several comments stating that it did not perform too well in low light.  Much of my work is in natural light.  I don't even own a light kit.  So that was a concern.  Do you feel otherwise?  After reading about this I started looking at Sony cameras because of the Exmor sensors.
I was also concerned about using the Canon plug in for log and transfer.  I am always wary of third party elements in the mix with FCP, where if something goes wrong there is a lot of finger pointing, Apple saying it's the third party element, the third party says it's FCP.  In your experience, is the Canon plug in a very reliable tool? 
I asked myself why doesn't Final Cut allow for imports from this Canon camera using its own log and transfer tool?  Why are all of the other cameras I am looking at in this price range creating AVC HD files that FCP's log and transfer tool handles without a third party plug in.
Perhaps I am wrong in these concerns.  Would love to hear that I am!
I am now looking at the Sony HXR-NX70, but sadly, this camera is not switchable 50 / 60 Hz.  Yet.  It is a new camera and Sony is considering whether it should allow for customers to send the camera in to make it usable worldwide.  The Sony HXR NX5E, which is switchable, is beyond my budget.  At least the NX70 comes with two XLR inputs and has full control of the audio.
So now I am trying to determine:  If I have a camera that only shoots 25 fps / 50 hz, can I in fact use that camera to create content for a US client that will only use that content on the web (i.e. it will not be viewed as broadcast television)
You mention that the The .mxf files the MX100 creates are XDCAM at to 50mbps.  I have been trying to understand how the 50 mbps aspect impacts final results.   Is there a quick answer to what the concerns are re this aspect on cameras.  Appologies for my novice level of knowledge on these things.  This is the first camera purchase...
Thanks in advance for any other thoughts you care to share, and thanks again for all of the detailed info you have already provided.