The difference in price on Amazon is $50. Huge difference in storage(HS 220gigs vs TM 32gigs). I'm leaning towards the HS version just for the storage reason, but was also wondering if since it's a hard drive if it's sensitive to bumps and shaves, or if I could run with it and film(carefully). Any thoughts or opinions on the matter?

Amazon.com: Panasonic HDC-HS900K 3 MOS 220GB HDD 3D Compatible Camcorder (Black): Camera & Photo

I have the TM900, but if the HS900 had been $50 more, I might have bought it. That said, according to the manual, the HDD requires a little extra care:

http://www.csportal.panasonic-la.com/descargaspla/PLA/DIGITALES//FILMADORAS//HD/HDC-TM900PU/DOCUMENTO/MANUAL%20DE%20USUARIO//HDC-TM900.pdf

"Handling of HDD [HDC-HS900]
This unit is equipped with the built-in HDD. While the HDD is capable of storing a large amount of data, there are a few things to look out for. When using this component, pay attention to the following points.

Do not expose the HDD to vibrations and shocks.
Due to the environment and handling conditions, the HDD may be subject to partial damages or may not be able to read, record, and play back data. Do not expose the unit to vibrations or shock, and do not
turn off the unit during recording or playback.If the unit is used in a place with loud
sounds, such as a club or similar venue, the recording may stop due to sound vibrations. Recording data on an SD card is recommended in these places.

Back up data periodically.
The HDD is temporary storage. In order to avoid erasing data due to static electricity,
electromagnetic waves, breakage, and failures, back up the data to a PC or DVD disc. (l 106, 119)
If the HDD experiences any abnormality, back up data immediately.Failure in the HDD may produce continuous noise or choppy sound during recording or playing back. Continuous use will cause
further deterioration, and may eventually disable the HDD. If these phenomena are
observed, copy the data on the HDD to a PC, a DVD disc etc. immediately and contact your dealer.
Once the HDD is out of order, data cannot be restored.

Operation may stop in hot or cold environments.
The unit is disabled in order to protect the HDD.

Do not use the unit in low atmospheric pressures.
The HDD may fail if it is used at altitudes of 3000 m or higher above sea level.

Transportation
When the unit is transported, turn off the unit and be careful not to shake, drop, or cause impact to the unit.

Falling detection
[ ] is indicated on the screen when it detects a falling state (a weightless state). If the falling state is detected repeatedly, the unit may stop the recording or playback operation in order to protect the HDD.
- HDD access lamp [ACCESS HDD] (l 12) illuminates while the HDD is being
accessed (initialization, recording, playback, deleting etc.). Do not perform the following operations when the lamp illuminates. It may damage the HDD or cause a malfunction in the unit:
-- Turn the unit off (remove the battery)
-- Insert and remove the USB cable
-- Expose the unit to vibrations or shock"

Thanks, that's good to know! I'm gonna go for the HS and if there's a possibility of a bump or running I'll switch to recording to an SD card.