I too have owned one of these for a little over a year. Like everyone else has stated, it is a little difficult to put together. About an hour and a half by myself. Two sets of hands are highly recommended. The main slow down in the process is the number of pieces, we're talking hundreds of them.
Before using it's helpful to read the directions carefully and maybe read up on composting in general online. Kitchen scraps should be chopped up as small as possible or as is convenient. Avoid meats, fat, and dairy, these things really aren't very good for composting and contribute a lot to smell. Also, cow manure makes good compost, dog poop does not. Do not put pet waste in your compost. You also have to remember to add brown stuff with your green stuff. That means dry leaves, saw dust, news paper. Too much green and your mixture will just rot and smell, not compost. Too much brown and your compost won't get "hot" enough to break down. You start to get a feel for it after a while and can tell by look and smell if your compost is swinging too far one way or the other.
As for this particular product, my complaints are these. 1) Difficult to assemble. 2) Difficult to turn as it fills up and gets heavy. 3) Difficult to unload. Due to the air tubes, you can't stick a shovel in there to get your compost out, you have to dump it out which can be awkward. 4) You have to plan ahead for when you want to use your compost and stop adding waste to it a week to several weeks in advance. And in that time you need an alternative compost plan or you just throw your waste in the trash. Some other composter designs are continuous so you never need to stop adding to them. 5) It leaks. Most of the time this isn't a big deal, as this "tea" is good for your plants and shouldn't smell too much. But if your mixture is a little too green, this leakage can be kind of gross, both in appearance and smell.
Other thoughts. Composting slows down as it gets colder. The microbes that break down the waste create their own heat but depending on where you live, it may get too cold for them to do the job. When that happens you may have to stop adding so you composter doesn't fill up. Also, you need to turn this thing every day or as often as possible. This is important not only for the compost but also for the composter. If the ball sits for too long in one spot with a full load of compost in it, it will start to dent where it rests on the base. It's easy to forget sometimes, or you may go on vacation. But you must keep turning it.
Final verdict for me is a 3 out of 5.