I've seen your posts before and thought you had an answer but IMHO I don't seem much difference in the brand. It boils down to a cost, sone rating, cfm, and looks of the grill balancing act(features and style). That is a decision I can't make for you.
I personally think you would be ok with 2.5 to 3.5 sone rating but less is better if you want to pay the difference. 70 to 100 cfm should be ok (45 cfm would be a minimum) but if you really want to move the humid shower air quick put in two except that it will create a draft.
I just put in two in a bathroom. They were Broan but forgot the ratings. Wanted a light above the tub so put in a fan/light combo with a light that was wet location rated. Wanted heat so put in a fan/light/heater combo above the stool. That way you can heat the stool area and bathroom with one on those cold mornings and run the vent above the shower to get rid of the moisture at the same time. For those daily constitutionals after eating mexican food, run both exhaust fans for quicker "relief"(present company excepted cause mine don't stink). Those 1500 watt heaters don't put out a great amount of heat but it helps.
Main thing is to use insulated exhaust duct and exhaust it outside the house, not in the attic. Also wire a heater combo on its own circuit.