Turin or Milan worth it?

You can take In the important sights in Milan in a couple of days. Torino is scarcely ever mentioned in this forum and is probably overlooked due it being off the straight path from Switzerland to Milan thru the Lugano/Lake Comp lake district.
When I am wanting to see what any city has to offer a traveler, I look at Wikipedia.

Turin is a great city. I’ve been in the area a few times and have not yet spent as much time as I want to in the city itself. The Piazza Reale is the place to start, with several royal Savoy palaces and museums. Then around the back of the Piazza are some Roman ruins. There are many kilometres of covered arcades, making it easy to wander past shops and restaurants. The Quadrilatero Romano is the older part of town and the centre of the restaurant scene.

The largest Egyptian museum outside Egypt, an interesting film museum, the basilica superga and its memorial to the soccer team whose plane crashed into the hill are all things I have yet to explore in detail. Just walking around is fun and the food is spectacular.

Great things to see outside of Turin that I have done - Le Langhe wine region, with its superb Barolo and other wines. Gorgeous drive. Stop In Cherasco, Barbaresco, Barolo, Neive, La Morra at a minimum. The Susa valley, especially Avigliana and above the town, Piedmont's provincial symbol, the pilgrimage abbey of Sacra di San Michele. That is an absolute must in my opinion, but not everyone agrees with me, as we had it almost to ourselves when we were there in July 2016. The Canavese region north of Turin, with some pretty villages, lakes, and more great wines.

So yes, I’d encourage a stop in and near Turin.

We really liked Torino. Went there twice while we lived in Italy. It is a more interesting city -- and more approachable -- than Milano, IMO. Great food, luxurious palaces, the National Museum of the Automobile is amazing as is the Egyptian Museum.

Another vote for Turin. A beautiful city with lots to see; much calmer than Milan. A visit to the Fiat Museum and the original Eataly are fun and just south of the main city.

We haven't been to Turin, but we spent 3 or 4 days in Milan this past summer, and loved it. Our hotel was out of the city center, so it was very quiet.

We loved the museums, especially the refurbished Duomo Museum. And we signed up for a City Wonders walking tour that included the Last Supper. Well worth the expense. We had the room to ourselves, and our guide pointed out a number of things we had never heard before. A great experience.

I loved Torino in 2015. Bad luck that we were there for Easter Sunday and Monday. I can't imagine how awesome it would be on non-holiday days.

I've been to Torino for long enough to eat lunch, which I enjoyed. However, I very much enjoyed my two visits to Milano, 1 night the first time, in 1995, and 3 nights in 2017. Torino gets so many positive votes from others here, I probably need to go back there before ever going to Milano again. Still, I found a wonderful necktie, pure silk, for €1 (one) at a secondhand/occasion/thrift store in Milano's fashion district.

Milan didn't do much for me personally - we stayed two nights, and one of our days went to Lake Como.

I will say - the Duomo is def worth a visit tho - and we went up on the roof - gorgeous. The Galleria next door is lovely as well, and we did enjoy the Sforza Castle as well. Otherwise, it was a very...business feeling city.

You could always daytrip from whichever lake you want to stay at and just spend a day there.