Hi,
With Vue you end up painting individual instances, whereas with the painted shader you're effectively painting the density mask for the population, and the populator still places the instances as before. You can get a similar effect to Vue's ecosystems by creating a number of populators with different models and using the same painted shader as the density mask for each. With the painted shader you can currently paint in the 3D Preview at any angle, wheres with Vue you only seem to able to paint in a plan view. It's still early days with the painted shader though and we may need to change the way it works in the future. It's not especially refined right now, but you can do some cool stuff with it nevertheless.
Regards,
Jo