Do ski boots fit the same from brand to brand or are they like regular shoes and differ a little bit?

I have tried on a few pairs of ski boots at a ski store. I was first trying on mens and they pinched my calves too much and the length was either too small or too large. I asked the guy if women's would fit better. He measured my feet again and got a pair of women's boots. They fit so much better. I tried on a pair of Solomon boots like are in the first pic. They want $600.00 for them. I have been shopping around on line and found a few other brands that are cheaper in price. If I didn't go to a ski shop in a ski town I would think twice about what we had discovered. Of course I shouldn't have been surprised by it because mens shoes never fit right either even after a professional tried helping me with regular shoes. If any one has any information about ski boots and sizing with the different brands I would greatly appreciate it. The boots I have found don't look any different than men's.