My understanding:

Saveset ALL will get the volumes and the OS specific requirements for 
doing a BMR (Bare Metal Recovery) - i.e., a "disaster recovery" type of 
recover.
Saveset ALL-NTFS will only get all mounted NTFS volumes; it will not get 
the VSS:* or DISASTER RECOVERY: savesets; these are REQUIRED to get a 
(Windows) BMR - Bare Metal Recovery.

If you don't need a BMR - i.e., if your disaster recovery method is to 
install the OS clean; install the application; recover the data - then 
ALL-NTFS will be fine. And that is a perfectly valid DR strategy, for 
certain kinds of applications. I have a number of servers where that would 
be the DR plan.

If, on the other hand, you need to recover what is essentially a snapshot 
image of the entire system, and have it Just Work after the recover 
finishes, with no further configuration or application re-install 
afterwards, then you almost certainly need an ALL backup. You would need 
that DISASTER_RECOVERY: or VSS:* savesets, to make this happen.

That's a bit simplified, but a good rule of thumb, as they say.