boots are all about FIT. because you are dealing with plastic boots (unlike snowboard boots) they come in a variety of widths from super narrow (95mm across the ball of the foot) to super wide (105mm) and everything in between. this is where having a boot fitter will help you because he will help select the appropriate width for you.
the more you spend, the nicer the plastic is (better flexing, more durable, better to stretch/grind if needed), the better the buckles are, and more importantly the better the liner gets. a nice liner will have longer lasting materials and have the ability to be more customized to your foot. good ski boots start around $350 and your best values tend to be around $500 and they go up to easily $800.
I usually bring a knife to a gun fight. Sometimes a sharp one.