Thoughts/things to look out for a condo in an older (heritage) building?

Not been looking at houses for too long, but we're trying to keep a very conservative budget while this market is down. Our favourite place so far has been an older building condo unit and we're super tempted. The layouts are so much nicer in these old buildings with actual kitchens and actual doors and a bedroom that you can actually fit a king-size bed in. There's even a set of pretty French doors!

However, the place used to be apartments since the 1930s, and then was turned into condos. Everything has been renovated with modern appliances and such, but that doesn't change the fact that the building is 100 years old. These types of units are so much rarer that I'm having trouble with my research. Anyone have experience or thoughts on these?