parrotlets, i have experience with
great small birds but they need BIG parrot attention. they need a much large cage than one would expect for such a tiny bird, and prefer a cage that is longer than taller with LOTS of toys.
hand fed babies are the best choice for a pet, but are a little more expensive than a budgie or teil.
they do however come in LOTS of colors, and have great big personalities. all the p-lets ive been around are typical parrots in the sence that they can be tempermental and have bad days, but are generally sweet, loving, cuddly and little tiny clowns, very playfull...
P-lets can speak, but ususally not very clear and when they do the pitch is so high they sound like tiny little robots!
noise level = LOW, these guys will make noise, and it can be noise thats suprisingly large for a tiny bird...but these noisy periods are usually few and far between, and short lived.
Boo, my temp p-let last year wouldhave about 2 minutes every morning where he would just squick and go on at everything in his cage...during that time you could hear him in other parts of the house (though not clearly), however the rest of the time, nothing...hed make soft chips and pips at me when out and snuggling...
budgies ("parakeets") make great pets, there is 2 types, the american style, ones youll be more likley to find here, which is a smaller, thinner bird, they can talk, but are more likely to pick up whistles and sounds than words.
and the english budgie, the english are a stocker bird with an "old man" type face (larger head and feathering makes them sometimes look grumpy. the english are however more likely to talk than the american (selective breeding)
both types are however the same bird, budgerigars.
unlike MOST other parrots, budgies are actually best bought as YOUNG parent raised birds, hand fed budgioes are often nicknamed "piranah birds" as they are not shy and belive all fingers = food
budgies are one of the easiest birds to tame from young even parent raised budgies will become extreemly people friendly when given the right anount of time and attention.
Noise level=medium, a single budgie alone will generally chirp and cheep but the volume inst enough to bother most people, get a pair though and it definatly increases volume.
green cheek conures...these little guys are about teil sized, and probably the only "apartment suitable" conure...
like all conures greencheeks can be loud (especially compared to their body size) however greencheeks are known for being "inactive" in terms of sound, generally they will have a moment in the morning and evening (typical bird noise times) and when their suprised/upset with something. these little hissy fits are generally short live enough to not realy bother neighbors.
they can talk...like plets they have little robotic voices, some greencheeks will and some wont talk.
they are VERY playfull little birds, they like lots of toys and a relitivly large cage, they also tend to become very attatched to their people and love attention.
they can also be quite the snuggle bugs
noise level = medium-high, they have a big voice for such a little bird, but compared to conures (and most other parrots) they are "quiet" birds and uusally apartment suitable.
parakeets (true parakeets including grass and linnies) (these are different form the "parakeets" sold in stores here in the us who arnt true parakeets but budgerigars)
like budgies in most sense, most of the parakeets arnt big talkers, but they make up for it (particularly the linnies) in personality, great little birds, low noise level.
one thing to keep in mind is cage size.
cages are ALWAYS marketed too small...
a cage marked "suitable for cockateils and similar sized birds is realy the MINIMUM size for a single parakeet, a parrolet needs a large finch/canary flight cage MINIMUM, teils and smaller conures need a cage thats labled for large conures/small parrots and those small parrots need a cage thats usually sold for small macaws...
always get bigger, just be sure to check the bar spacing.
personally i want another p-let (i fell in love with boo), a greencheek, or a hahns macaw.
but ive also put thought into a lovebird, and liniolated parakeets...