The two doors, especially the one on the top ar really handy. I have several cats that I have trouble getting into carriers, but with the top door I just sit them down in it. Works great.

Pros: double doors

Cons: none

I love the lop loading door. That way I can just open it up and drop them in. Or if they do not want to come out of the carrier it is easy to pull them out.
I also use the carrier as a little portable kennel for my bottle kittens. The top door makes it easy to care for them and when it is time to go then just close the top and off you can go.

Pros: easy access

Cons: top door may not latch well

I use the top door more than the side door when I carry the cats or kittens to the vet or to get them set up in a display.

Pros: Like the different sizes

Cons: none

i use this for my dog. for when he is either in trouble or we need to keep him in it for the times no one is home so he doesn't get into anything. when he's not in trouble and thinks he is i can get to him easier through the top door and reasure him that its ok for him to come out.

Pros: easy to get to the dog

Cons: none

Our veterinary clinic has used these kennels for about 10 yrs now. They clean very well, without rusting the doors. Regardless of the disinfectant used. They are easy to take apart and put back together. The top door is great for taking cats in and out of the kennels. It is a bigger opening than trying to take them through the front door. It also allows the cats the ability to see more. Very great product. Very durable, and a must for any cat owner who has a difficult cat to put in a kennel.

Pros: Top loading door

Cons: Can crack at top over time