Comfy feet are happy feet, cold feet or bleeding heel blisters can ruin your day. My favorite snowboots ever are my Merrell Isotherm Mids from 2012, but sadly they have been discontinued.
Here is what I look for:
-- Roomy toe box, anything tight will be cold.
-- Size up 1/2 to 1 size (forget the number, staying warm is paramount!) to allow for sock thickness, a different insole, or foot warmers.
-- Consider how high you need the boot to be. Most urban walking will be on shoveled sidewalks with the occasional snowbank where your leg sinks up to the knee scooping snow over the top of your boot (ugh!) or puddle at the curb that has a hidden 3" pothole, when you expected 1/2" water. OTOH, I find boots that come higher than 5 or 6" restrict my ankle movement, which is important for negotiating uneven and slippery surfaces, so I prefer gaiters with snow pants for deeper snow.
-- Soles must have good traction. Low wide heels when viewed from the back. (I don't find wedge heels to be very stable).
-- A waterproof base is essential, the higher a rubber bottom comes the better.
-- An insulating layer, and thick sole. Cold seems to mostly come up from through the sole.
-- Breathablity when you will be wearing the boots for more than 15-20 minutes.
-- Convenient on-off. Call me lazy, but bending over and getting my fingers in between tight laces gets harder as one ages (and you have to take off your mittens). I like either a slip on that seals with a snug top, or boots where the top attachment is a hook so you can unhook and rehook the laces without retying them.
-- Sport use is a separate topic, but I appreciate my Merrell Isotherms' D-ring at the front of the laces for attaching gaiters, and heel groove for my snowshoes.
Although LLBean's duck boots are in low supply, some sizes and colors of their Storm Chasers are still in stock. I've had a pair of the Slip on Storm Chaser Shoes for over a decade, and they are great for 2-3" of snow or shoveled sidewalks.
Also look at men's or boys' boots if you can find your size.
Boot add-ons to consider:
-- Good socks! or a thin liner sock and thicker insulating sock
-- Gaiters for deeper snow - a nice pair at REI http://www.rei.com/product/846.....ers-womens
-- Yak Trax or other crampons for icy conditions
-- Toewarmers or Footwarmers