Both my cages are a mottled gray, and that works for both me and the birds. Size - get the biggest you can afford. And features depends on you and your bird. Boo's first cage (now the dove's cage) was a dome-top with just the front door. I never closed it, he was allowed in and out as he pleased. His favorite place to perch was on the door, outside the cage, and his poop missed the cage completely and landed on the floor. That was a problem. So I got a much bigger cage that's half dome-top and half play top. The dome top opens up and half of it is permanently wedged open so he can climb clear to the top (about 7 feet off the floor) and perch there. There's a side door that opens from the cage to the play top, and that door is permanently latched open, so he can climb there if he wants. The play top has a perch and a couple of spots for food bowls. Then there's the cage. The main door, on the front, stays closed, but he can still get out any time he wants through the top or the side. He likes the new cage better. Sometimes he perches clear on top, sometimes on the wooden perches inside, sometimes on the playtop. He doesn't feel confined, he's got plenty of toys, and I put his food bowl on the playtop and his water down in the cage, so he has to climb around and be active to meet his needs. I shopped around quite a bit and found one for about $500 - I'd seen the same cage priced as high as $800.
Some people prefer to keep their parrots locked in, unless they're right there to watch. It's not an approach that would work with Boo, but it works for them. If you're one of those people, this cage would probably be overkill.
