HI there,
Been twice and enjoyed both times. 1st time stayed on site expensive but good:
https://www.nh-hotels.com/hotel/nh-milano-fiera?
2nd time, in Milan central, right next to the main train station in a wonderful old hotel full of style & Character:
https://en.andreolahotel.it/
Trade show is gigantic and will tire you out, did two days first time and still never saw everything - single day with more sight seeing last time was more relaxed.
Metro ticket we bought was costly as we didnt realise it DID NOT cover travel to the hub for the EICMA bike show and we were quite heavily fined by the rail police who were out in droves waiting for such easy pickings!
Sightseeing:
The Duomo is such an awesome building, go to the side entrance for paid roof access.
National museum of Science, has lots of interest but we never made it.
Planetarium: nearby but couldnt get in; fully booked.
Check with Ducati if possible, there is a local club organise a night club event during the EICMA weekend, what an eye-opener at this club:
http://www.ilgattopardocafe.it/
I used a tablet with a city mapping app on board and, first time ever - NEVER got lost once!!!
Enjoy