Cockatiels are easy and the least aggressive Parrot. The males talk the most and its not really clear but they are vocal.
Conures are great too I plan to have one for my next bird. Their very smart and learn to speak easily from what I have heard. They are great birds
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Some African Greys can be sweet but its just like with a dog its all in how you raise them. Really that goes for any parrot anyone can be mean if they don't get tons of attention, training, and love.
Alot of Parrots are like kids they are needy and when they don't get what they want they can get nasty.
Macaws are sweet but they are high maintenance and require ALOT of attention so they do not turn out mean. Also socialization if you want to be able to trust it with guests.
Really I am a huge parrot buff I have read up and been around jsut abotu every kind you could think of. I have had Cockatiels and an African Grey who was very sweet named Peanut. My mom has a friend who owns three Macaws, 1 Cockatoo, 4 Conures, and 7 Cockatiels. I have helped her take care of all her birds and teach them and socialize them.
In my opinion Parrots are more work then dogs lol.