Was quite nice I thought - some interesting historical sites and (for us) the obligatory mortuary. Puerto Montt was a staging post and we didn't get much time there - reminded us a bit of a satellite town. Still in spectacular country though.
Got to the mortuary - definitely some spectacular relics there. Punta Arenas seemed fine though its centre was a bit dead in the evenings; I think the big shopping area on the north edge of town (Zona Franca) has sucked a lot of the life out of the centre.
Dead in the evenings? We arrived about 2pm on bleak Saturday afternoon which made transport easy (little traffic) but little atmosphere - I guess a bit like centre of Canberra on a winter weekend. Went to Brown House, Falcon Scott's monument and next day(?) penguin rookery. Nice views overlooking city too.
Is Peulla on your itinerary? Be careful - timing is important there - check ferries etc! if so.
Saw some of those overlooking views on my run this morning.