My 2-cents and my thoughts will echo some of the comments already posted.
EDIT TO ADD: After seeing the length of my post, you're getting close to a nickel.
Frost-free suck. Food won't last long at all and things that are sort of soft anyway (e.g. ice cream) will get crystals growing on them.
Defrost mode. This is a switch you flick when you want to defrost the freezer. It's worthwhile but not really necessary.
Upright pros/cons. Yep, easier to get to stuff. As already noted, when you open the door, all your cold air escapes. When that happens, your freezer frosts up quite a bit and requires more times defrosting. Probably at least 3X as much as a chest. You'll also encounter a bit of the defrosting situation of crystalizing on soft items or loose items in plastic bags.
Chest pros/cons. A little harder to find things so you need to keep it organized. Don't let Mrs. Doc use it. She'll throw the weekly groceries on top for a few weeks and then you can't find anything. Let her use the upright. Again, go with a deep-freeze. No auto-defrost. Since the cold air stays in when you open the lid, it gets very little frost. I have the biggest Kenmore they make and an annual defrost may yield a small pail of frost when cleaning. Probably 5x that on a similar sized upright.
Brand. Hmmm, I have Kenmore and Frigidaire. I've never had a problem with either over many years. I run mine at right around 0° F. I also buy one of those little LCD thermometers with the wire to a sensor. The sensor is inside and the LED is outside so I can glance to make sure temp is good without opening the door.
Upright vs. Chest? If you have the floor space, get one of each. If only one, I'd get the chest if it's long-term storage and upright for short-term. The upright, opened frequently will require defrosting every few months. Long-term in a chest can go more than a year without defrost. I do it annually just to check stock and reorganize.
Cleaning. I use a plastic spatula and a towel to soak up the water. Be careful where you use a spatula on an upright since the racks are actually your cooling fins.
Thoughts. Personally, I have the biggest Kenmore chest made. Have 2 of the largest Frigidaire uprights they make. Ran out of space last fall getting a cow and had to buy a mid-sized upright for overflow. Once we eat enough beef, that one will be shut down.
So we run 4 deep-freezers as well as 2 full size fridge/freezer combos and an apartment sized fridge. Generator is a must have!