I have an african grey named Sophie, she's just over one year old (13 months) and let me tell you that it has been a tremendous adjustment to my life.
I've had plenty of animals, from fish and reptiles to cats and dogs... never have I been more stressed, spent more money and felt more frustrated with another animal. Forget about the cost of the bird itself, the monthly toys run me at least $150, and every 2 months or so I have to place a big order on the big toys that usually leaves me with a $300 bill along with various foods (I feed primarily Harrison's Organic) and supplemental treats.
The bird is quiet when alone or busy with a toy but it will get very loud and moody to get your attention. Sometimes it can become incessant and overwhelming when you have serious work to do and you have a screaming bird in the background.
Birds also poop just about everywhere and anywhere. You will have to constantly clean your floor, furniture and just about any surface you let your bird on. African greys are also very dusty, they will shed lots of dust particles.
They are destructive... I have to constantly make sure no electronic equipment is anywhere near the bird. Your eyeglasses, watches, necklaces and any other adornments you wear are in danger! One mistake or lack of attention means your $5,000 watch now needs a $500 repair or you will need to replace your brand new eyeglasses.
Worst of all, these birds are incredibly intelligent and requires lots and lots of psychological and intellectual stimulation. I learned that the hard way when back in February, she began picking and breaking her feathers (in half) and it seems that she is now progressing to fully plucking them out.
This behavior literally jumped out and smacked me in the face, from ABSOLUTELY NO WHERE! Everything was fine and dandie one day and the next day I found her "preening" and 100 broken feathers on the floor. I panicked and called the vet immediately. After extensive health screening and testing ($700 bill), the vet found no apparent cause and suggested that it may came from boredom or irritation that manifested itself into self destructive behavior. Worst yet, it's not always reversible with increased interaction and stimulation because the feather picking and plucking can easily turn into a compulsive habit that remains for the rest of the bird's life.
So my first advice to you is DON'T GET ONE. Or if you do, get it from a reputable breeder. My breeder is in Miami (I'm in New York) and I have yet to ever receive the proper paperworks from her and she has not offered any help with my situation.
But with all that said and done, I couldn't be more happy with another animal. Nothing is quite like that of an African Grey (or intelligent birds in general). Sophie began talking as early as 4 months old and she's very bold for her species which is known to be timid and fearful of virtually everything. She's very very sweet and wants nothing more than being loved (and toys, lots of toys). I think the only thing that can compete with her would be a human baby.
Think long and hard before getting one. I have a short temper with barely an inch of patience to spare... not exactly the right combination with a stubborn and strong-willed bird. I got an African Grey because I only read and heard all the positives of owning these intelligent animals, and it all culminated into this fantastical image of a pretty parrot sitting on my shoulder and eating out of my hand... but sometimes the real world can be daunting and even though I love this bird, I honestly would not have been ready to deal with the unexpected issues with owning an African Grey had it not been my supportive girlfriend. She's not a big fan of my other pets but she absolutely adores this bird and whenever I become overwhelmed, she manages to bring it all back together and remind me that Sophie is just a baby bird and being gentle and calm is the only way to get the bird to stop screaming and yelling (and yes, they can and do bite!)
There is a reason why many of these birds often go through multiple owners before they even become mature adults... don't let yourself be the one to get a pet parrot only to abandon it later on.