I raise llamas and they are completely quiet. You can hear them humming but only when you are pretty close to them. They poop in the same spots so they are easy to clean up after and they don't smell unless you don't clean up after them for a while.
They are very social animals however and have to have at least one of their own kind to be happy and healthy. So, you need to have at least two. As mentioned, I would suggest against having an intact male, unless you have two intact males or one gelded and one intact male. Do not have a female around an intact male. My friend packs with a string of 8 males (most of them are intact, a couple are gelded), they all share the same pasture and obviously pack together. They get along fantastic and are best friends... until you get them around a female (like when I brought two here at the same time to breed to my females) -- they become hard to handle, potentially dangerous raving lunatics. The two males I brought here spend every moment of every day literally trying to kill each other. I had to take one back home so the other one would even breed my females. Once they were both back home together - with no females around - they were best buddies again.
Llamas are normally very fence friendly. (Except for those intact males trying to get to a female - I watched a male jump easily over a five foot fence from a stand still.)
Llamas are easy to feed. Only give them grass hay, never alfalfa unless it's a rare treat. You can give them special llama feed or grain but don't need it unless they are pregnant or nursing.
I also have Alpine and Nigerian Dwarf goats. In comparison the NDs are far less noisy (loud) but far more vocal than my Alpines. That's just my experience. I love my goats - their incredibly outgoing, get-into-everything personalities just crack us up and make them so lovable. You can milk NDs but it certainly is more of a challenge than a full size goat just due to their small size and small teats. They do have a high milk fat content, like Nubians.
Goats are like llamas in that they are very social and also have to have the company of another animal they can play with... another goat is by far the best solution. Goats require very good, strong fencing but are very easy to care for. I also have horses and would disagree with the poster who said they are harder to clean up after than horses. My goats are far easier to clean up after than my horses. I use a shrub rake and shovel for dry ground and a pitch fork for the straw areas.