Better is up to the owner. I don't think the bees care.
Square was easier to build for me.
I could mix with lang deep if I wanted.
I do think the sloped ones are more attractive for a backyard setting.
I don't have a problem with the bees attaching to the sides, although you will hear that concern.
doug, I'm wondering about your experience with this square TBH. How durable do you find the comb when under manipulation? can you handle them just the same as the trapezoidal shaped ones?