A freezer with an evaporator system will keep food better for a lot longer than a freezer with a defrost cycle. A freezer with a quick temperature recovery time after opening will keep food better for longer than a slower, less precise one. I don't know the stats on the particular models you mentioned, but I suspect that the answer is yes for the higher level columns.

(I don't say "fresher" because the legal definition of "fresh" means never frozen and that keeps rattling in my ear as I write.)

Maybe I should have said "preserved" :) Do all freezers have evaporators?

All freezers have evaporators but not all have self defrost.

I called Subzero, and it sounds like their unit's defrost is similar to other manufacturer's.

As I understand it, there's the kind of freezer that has "self defrost" where the cycle literally defrosts the way one does it manually, though while the food is still in there. That is, the freezing cycle stops and the temperature raises so that the frost build up can melt and drain away. The other kind uses the evaporator to remove the moisture from the air while it's good and cold so that it doesn't have to warm up the food. I worry that Jakvis, who I'd thought was up on tech, seems to have said otherwise. Maybe I don't understand it correctly.

I can say that my Miele column, which is supposed to be the second kind, never opens to a temperature above the setting, by my Taylor thermometer which is mostly in there just so I won't misplace it now that I have good appliances, unless the door has been opened for a long time.

I have a free standing manual defrost freezer, too. Since I've been using it for long term storage, rather than opening it several times per day, similarly holds a nice low temperature and keeps the food a long time. Most of the difference is convenience of location, and the kind of things I keep long term aren't so delicate (stock, soup, spaghetti sauce, lasagna, etc.). Because the Miele is constantly being opened, bread and small pastries will get freezer burned more quickly (i.e., in a matter of months) than in the manual defrost, which sometimes goes weeks without being opened. Otherwise, they're fairly comparable.

What is not comparable is a self-defrost unit. Things go weird pretty quickly in a self-defrost.

According to the Subzero tech, their freezers use a sensor and run defrost only when needed. I wonder is Frigidaire, Whirlpool, GE, etc. have these sensors or still use the timers? Thanks all, I am learning a lot!

Almost all manufacturers has gone away from a mechanical defrost timer for home refrigeration. It's still found in commercial units. It's much easier to hit the energy requirements with adaptive defrost (sensors) Adaptive defrost has been around for about 20 years now. Many, many years ago there were some refrigerators made that counted how many times the doors were opened and then defrosted when the count was met.

I've also run across the mistaken belief that a fan runs to circulate heated air during defrost (and around the frozen food). No refrigerator or freezer I've seen does that. The defrost heating element is hidden behind the rear panel in the freezer compartment and is mounted under the freezing (evaporator) coil so heat radiates upward across it to melt the accumulated frost. A thermostat mounted near the top of the evaporator turns the element off when a target temperature is reached behind the panel.