Is this parka warm enough for subzero winters?

Yes. The down and feather fill plus the long, hooded design is built for deep cold. It is warmer than Lands' End's lighter down coats, at the cost of more bulk.

How does it compare with The North Face or Columbia parkas?

It is warmer and longer than most of their everyday down jackets, but heavier and less packable. Those brands suit active use better; this one suits standing around in cold.

Does it run true to size?

It is cut roomy to allow layering, so many owners take their usual size. Size down if you want a closer fit over thin layers.

Can it be machine washed?

Yes, but use a down-safe detergent and dry it thoroughly on low with dryer balls. Poor drying is what causes the fill to clump.

Is the shell really waterproof?

The shell is waterproof and handles snow, sleet and wind. Seams and the hood are the weak points in sustained rain, so it is a winter coat rather than a rain shell.