I had lots of problems with both nvidia 270.41.06 and 270.41.19 versions and had to drop back to 260.19.44, but other people have been trouble free.
Whilst in Synaptic do the normal Reload and when you get the list back, select
the nvidia driver and then go to the menu > Package > Force Version - now use the dropdown box which should show you the 2 versions.
If you decide to upgrade and things go a bit skewiff you "should
" be able to do Force Version and drop back down.
Anyhow, that is how I did it.
I must say this is the very first time I've had any problems with the nvidia drivers and was a mite surprised when it did happen
Live and learn.