I just wanted to say something than another member wrote somewhere on the M10 thread;
It is a good idea to use an external memory card because the internal memory may stop working after using it multiple times.
Once it is dead, it will be probably very hard or even impossible to replace it.
That will eliminate the cross-memory recording option or in case you lose your card, you are stuck until you buy a new one.
Micro SD cards are really cheap right now and you can buy an 8 GB one for less than $20.
I think it will be a good idea to buy one and use it as your first memory option and only use the internal memory when you have to.
External cards can always be replaced for cheap...