Ah, I see them now. Hm, my personal opinion is that they are not high enough for most bunnies to stretch properly with a lid on, and are too low to keep a lid off. They are one panel high, which is generally 14 inches in the CC panels. What breed of rabbit do you have though?
I also think that as far as price goes, you actually get more bang for your buck by buying and assembling yourself, but that depends on what materials are available to you and your ability to build a base (their bases are corragated plastic cut to fit the frame. I would worry about those being chewed as most CC cages for rabbits extend the base at least an inch past the frame to prevent bunnies chewing on materials they sometimes like the taste of like thin plastics, some like wood, most like paper based things, etc). Also, with a lid on, taking out that tray to clean might be hard to impossible, especially if you want just a small door.
Is your rabbit litter box trained? If not, I might stay away from the CC cages, as rabbit urine will break down the bars where they sit on the ground. If so, these types of cages are easy to clean, but only if sized right for the animal with good access points for you.
For doors, just designate one or two (I recommend two for ease of getting in there to clean or fetch a rabbit) panels to act as a door either on the top or the side. Cable ties work great as a hinge, and you can buy small clips to keep them securely fastened.
