I would go with the largest aperture. In this case it would be the 150mm.
The price difference from what I see is minimal as well.
Just be aware that Newtonians on EQ mounts can get a bit " fiddly" when you are not used to them.
But that would be my choice. Just persevere with the EQ mount and enjoy the 6 inch aperture.
Also an EQ mount is a little easier to track the Earth's motion than a dobsonian mount is.
But you will need to roughly point the axis of the EQ mount to the South Celestial Pole to make tracking a bit easier.
150 mm is my choice.
Enjoy.
Geoffro.