Zach & Dani's has a smokeless design with their catalytic converter. This is a BIG plus. It's quite a treat to roast indoors without worry of setting off smoke alarms.

Cannot adjust timer other than to add minutes to the default setting of twenty. Machine has a fairly large footprint. Some chaff always found it's way onto the counter while roasting. I could live with all of the above, but bottom line is the taste of the roasted beans was not to my liking (see commentary below).

I bought the Zach & Dani's roaster to "upgrade" from a Fresh Roast machine that I'd been using for three years. The reviews of Zach & Dani's seemed to favor the lighter roasts (which I prefer) and the machine had a "set and forget" design, greater capacity and NO SMOKE!
If for no other reason than roasting indoors without sounding smoke alarms, this is the machine to get. The noise level is comparable to my Fresh Roast machine, which is pretty good. In cool down mode (the last 5 minutes of the roast cycle), the rpm's kick up and it gets a little noisy.  To me it sounds like someone is vacuuming in the next room.
My first roasts with Zach & Dani's were noticeably flat tasting. The manufacturer did tell me that the slowness of the roast emphasizes the body, and may de-emphasize the acid. Well, for my palate, the brightness was completely gone - this was one dull cup! I tried their suggestions to pre-heat the roaster and/or use fewer beans. Both of these techniques are to allow for quicker roasts, and to maintain some of the brightness. This improved things only somewhat, but cup quality and flavor was still well below what I was used to with the  Fresh Roast machine. Setting the timer on the fly also negated the "set and forget" advantage by requiring monitoring of the roast time. Just for the record, I did numerous "A/B" roasts with the same beans in both the Zach & Dani's and Fresh Roast and the results were fairly consistent.
So is this just a matter of preference? The Zach & Dani's rep acknowledged that I was probably used to the brightness in the roast of the Fresh Roast machine and theirs is a different method of roasting. After all of my tweeking, there remained a similarity and a one-dimensional quality to the Zach & Dani roasts.
Something else I found annoying is how finicky the placement of the seals seem to be during roasting. No matter how well I tried to seat the seals, I could not completely eliminate small amounts of chaff from blowing out of the machine while roasting. This may not bother some people, but that's one more thing to clean up.

Zach & Dani's made good on their 30 day satisfaction policy and handled the refund cheerfully and promptly. They gladly supplied info in my seach for a better tasting cup. Customer service is to be commended.