It will work with several native shaders, though you won't get the same level of control as converting them to Corona Materials (and since that can be done with the included conversion script with the click of a button, no reason why not to do it!) With Corona as the selected renderer, the material list in Slate will show which are can't be rendered (quick grab attached)
Good grief on the list of improvements since the free alpha! Too long a list to mention :) The best summary would be to have a look at the road map at
https://trello.com/b/EfPE4kPx/corona-road-map-3ds-max which shows from version 1.2 onward. Primarily, much faster, much more stable, much better handling of many lights, denoising, better scattering, better displacement, render regions in the VFB, and the list goes on, and on, and on....
You could also use, for now, the Speed page on the website, which compares the alpha to 1.0, while the road map above will take you from there to the changes of today (
https://corona-renderer.com/features/speed/) - a page that will disappear at some point as it is rather out of date with where things are now.
And the YouTubes for each release
1.2
1.3
1.4