Another round of fixing and polishing to MPS 3.0 has just been finished and packaged into an EAP release. Get the most recent EAP release from the download page so you may give it a serious try.
Check out the list of all fixed issues in this release.
The final release is just round the corner.
We also bundled several new sample projects that let you play with multiple editor projections, type-system or mathematical notations. They might be a good way for you to try 3.0 out.
You can read more on the bundled sample projects in the documentation.
Develop with pleasure!
-JetBrains MPS Team