Round pans distribute the heat evenly, square pans have cool spots in the corner which can be a good thing or a bad thing depending on what you are cooking
I find a simple steel
wok the best for most cooking
. It heats up very quickly and cooks fast like a stir fry which saves gas on those long ocean voyages. You can use it as a steamer with a bamboo basket, although be careful in heavy seas. With a foil covered wire tray I have even used them to bake a cake and cook biscuits. I will get around to try and bake bread one day. But you have to be familiar with the idiosyncrasies of your stove and wok and be prepared for a few failures until you learn them.
About the only thing they are not really suited for is a wet dish like a casserole. For those I use a pressure cooker, which also cooks fast and saves gas.
Its not strictly non-stick but a well oiled and cured wok can generally be cleaned with just a vigorous wipe with a wet cloth or paper towel, thus also saving on water
You can buy traditional ones with just holdons or proper insulated handles. They come in a variety of sizes with flat or rounded bottoms (I prefer the rounded so that any fat drains away as I push the food
to the side. )
You can buy fancy ones for high prices at the kitchen stores or get a dirt cheap
one at just about any asian food
I love my wok. At home, on land, I use an electric
one because I dont have a hotplate.