Different winter coats are better for different activities. Skiing/snowboarding coats can be warm but will also have a lot of ventilation and may he more expensive due to all the features. If you walk around a lot outside, longer jackets are really nice. Mid thigh length at least will help you keep your core warm. The very long parkas can be inconvenient for a lot of walking for say commuting but may be very cozy for casual dog walking. Wind proof is a must have. Puffy coats tend to be wind proof but not always water proof. This is again where the pirpose of the jacket comes in. I live in the Boston area and have a great knee length Patagonia puffy jacket for commuting. It's super warm and relatively light weight but not very water proof. I also have a ski jacket that is very water proof, perhaps a bit heavier physical weight wise and is shorter for better movement while doing snow sports.

Always try on a jacket with a layer or two. If you want wear a fleece or sweatshirt underneath it's probably too tight. Brand wise, anything carried by REI will serve you well, including their store brand. LL Bean is quality but not as fashionable. Good luck!