The simulator you do your MCC is irrelevant. What is more important is the quality of the instructors and the course they have on offer.
My feeling is if you do your MCC on say something which is not to overly complicated to fly then at least you can concentrate on the actual CRM aspects of the course which in essence is what the course is about and is a hard skill to master.
Even though the course is a tick in the box, what you put in you will get out. So before going on the course know the SOPs , Memory Items, Flows , where to find things in checklist etc.
Also, in my opinion whether it’s done on EFIS or Dials is irrelevant.
If you can fly the plane using dials and raw data you will have no problems flying an EFIS type aircraft compared to if you were going from EFIS to dials