Welcome to the forum!
Go with the square coop, seriously. I recently built a small A-frame, and it looks really cool. I wanted it for 4 standard sized birds but when it was done, because of the slopping sides it just wasn't big enough. I now have three bantams in there.
Roosting space and ventilation are also a problem with the A-frame, the roosts have to be pretty low down to make sure that there is no draft from the ventilation on the birds at night. The birds can't roost as high as they would like to.
I cleaned both of my new coops (A-frame and square) for the first time today and I have to say I found the A-frame easier. One of the sides lifts up on hindges, then I just scraped everything out into a waiting wheel-barrow. Took me 5 minutes. The square one was more difficult as the old litter and dropping where in the corners. If it's a large coop where you would be able to stand up inside then cleaning a square coop isn't a problem.
The only way you can get away with the A-frame is if it's huge, or if it's just for a couple of bantams like mine.