Here is the three compared to one another on Newegg (http://www.newegg.com/Product/Productcompare.aspx?Submit=ENE&N=40000205&Description=vixia&bop=And&ActiveSearchResult=True&CompareItemList=N82E16830120227%2CN82E16830120291%2CN82E1683 0120313)
And the HG10 and The HG20 both have HDDs. But can I also record to the flash card. And is it a hard drive or a ssd drive or internal flash memory? any help would be great

I think I am really leaning toward the hg10 or the hg20 because the added price for media isn't that appealing for the hf200. Any thoghts?

Here is the three compared to one another on Newegg (http://www.newegg.com/Product/Productcompare.aspx?Submit=ENE&N=40000205&Description=vixia&bop=And&ActiveSearchResult=True&CompareItemList=N82E16830120227%2CN82E16830120291%2CN82E1683 0120313)
And the HG10 and The HG20 both have HDDs. But can I also record to the flash card. And is it a hard drive or a ssd drive or internal flash memory? any help would be great

I think I am really leaning toward the hg10 or the hg20 because the added price for media isn't that appealing for the hf200. Any thoghts?

See the coloumns: Recording Media & Memory Card

Best way to decide would be to consider haves and have nots of each camera, and see which outweighs the other. If quality is a concern, then read the reviews for them at http://www.camcorderinfo.com/content/Canon-Vixia-HG20-Camcorder-Review-35510/Conclusion-amp-Comparisons.htm

HG20 uses a magnetic HD which can be upgraded and/or replaced easily. You will have issues if it is mounted to something with vibrations. Thus, the advantage of SSD's.

Cmos Sensor size? what is good, what it better? how can I compare them, I've never delt with camcorders reallly

should be bigger the better. Although the newer models (do not remember which) have a smaller sensor (less low light performance) but have higher resolution by a large margin. Wonderful world of trade-offs.