The 6610 always comes with a Swiss dial, which is not the case on the 1016.
The 6610 has a lollipop second hand.
The case is a bit smaller on the 6610 ( 1 mm less, but I have to check ).
The movement of the 6610 is not hacking, while, on the 1016, it is hacking, from the years 1970.
And a few other details.
Best,
Nicolas.