First, let me say that I posted details of my first 15 roast on alt.coffee. I won't repeat the process here, but instead will give my general impressions after a month and a half of use.
The Zach & Dani Roaster seems designed for people who just want to roast their own coffee without thinking about it too much. As such, it performs very well.
When filling to the "fill" line on the roast chamber, it takes about 8 standard coffee scoops of beans. Depending on bean density, this is about 4.5 oz. The yield averages about 11 scoops of beans, weighing about 4 oz. The weight of your roast load here is less important, I think, than with other hot air roasters, because this one does not depend only on the air to agitate the beans. The screw rotor in the center handles the bean movement, giving the very even roast that this machiine produces.
This roaster is good for me, because I like light roasts. I dislike dark roasts almost universally, so keep that in mind when deciding whether my comments pertain to your situation.
When plugging in, the default time set on the machine is 20 minutes. That means 15 minutes of roasting and 5 minutes of cooling. You have the option to increase the time up to 35 minutes, but you cannot decrease it. It you want to decrease the roasting time, you may press the "cool" button to start the cooling cycle at any time during the roast.
The instructions recommend that no beans be roasted less than 20 minutes on the timer.
I have found that most 20-minute roasts produce a nice, even City Roast that lends itself to the bright winey coffees that I prefer. 22 minutes seems to smooth them out just a tiny bit, but I am not a pro cupper and it may just be a taste illusion for me. However, the general results, over time with this machine are very good in the cup.
When first using this machine, I found that the pre-ground aroma of my beans was hardly there at all. Nothing like what I was used to smelling with the beans I roasted in the Fresh Roast Plus. However, since this doesn't seem to transfer to taste in the cup, no big deal.
The Z&D offers a patented "catalytic" smoke reducer. I have been unable to read the patent for this device, so I can offer no details. I do my roasting outdoors (sunny Southern California), so this is a feature that, for me, is somewhat irrelevant (though may be of great importance to others). I can tell you that I did one roast, putting the machine in the same room as a smoke detector. The detector went off, even if there was no visible smoke. In addition, there is a strong roasting aroma, which, if confined indoors, will be overpowering to some people. It is quite strong outdoors as well. (And as a general note, I think all roaster makers should include in their instructions: "RoastING coffee does NOT smell like roastED coffee.")
After nearly a year with the Fresh Roast Plus, I had learned to listen for cracks to determine the roast progress of my coffee. However, with the Z&D, the cracks are almost completely inaudible. The only variable you really have to work with on this maching is the roasting time. You might lessen the bean quantity to obtain a darker roast (suggested by the maker, but since I don't like dark roasts, don't ask me). Or, you might stop the machine before the cooling cycle kicks in and cool them by hand. Many users have suggestd that the 5-minute cooling cycle is too long, resulting in a baking of the beans at the end of the roast. If true, this does not seem to matter to my taste buds.
During the cooling cycle, the auger rotates faster and the air blows harder. It seems to cool the machine very well, and I find all the very hot metal parts are perfectly handleable when the machine finally stops. In addition, this fast agitation shakes loose a lot of chaff, so when you toss the beans a bit (which you should do), a lot of excess chaff comes off, and you get nice clean beans.
Because you cannot hear the cracks, I would suggest that this NOT be the first roaster you try as a beginner. It just doesn't teach you anything about roasting. With the Fresh Roast Plus, you have a much shorter roast time, so each of your "lessons" takes less time. You also have a smaller roast quantity (about 5 scoops), which means you ruin less coffee when you make mistakes.
However, you must watch the FR+ like a hawk. On the Z&D, once you have determined an ideal roast time for a given coffee. You can set it and forget it. I find this VERY convenient when I am working (I write for a living). I can get a roast going, go back to work, and not worry until it is done.
One caveat on the walkaway feature. Sometimes, a bean will get stuck under the bottom of the auger, jamming the machine to a stop. The instructions warn you of this. All you need to do is give it a jiggle and it will restart. But this means you should keep the machine at least within earshot. You also need to be very sure that all the parts are perfectly seated. I had one ruined batch when my roast chamber was not set to its alignment pins properly, and I started the machine and just walked away. 20 minutes later, I had a batch of lukewarm green beans.
The instructions for this machine tell you to wash it after every single roast to keep it operating properly. This is totally improbable in the real world. You can put the business parts of the machine in the dishwasher, though.
Though I don't like dark roast, I do like an occasional espresso. For this, I have roasted straight Brazilan, with the machine set to 24 minutes. Makes a beautiful cup, so no complaints. However, since espresso is not my #1 coffee drink, take that into account on this comment.
The quantity roasted, which comes out to an average of 11 scoops, is very good for me, in a two-coffee-drinker household, where I drink most of the coffee.
And, although I recommend the Fresh Roast Plus to beginners learning how to do roasting, I myself now use the Z&D more than the FR+. It is simply more convenient. The FreshRoast remains for roasting smaller quantities and when I want to play around with first crack, second crack and so on.
I would like to see Z&D improve their model by adding more heat. I think the auger system is great, but I'd like to be able to speed up the roast time.
Note that this product is offered to the general public via an infomercial. The pitch is somewhat insulting to the intelligence ("4 payments of only $49.95... but if you act now... only THREE payments...."), but the product is very good.