Been looking for an upgrade to my Freshroast for awhile - had my eye on a Z&D for awhile, but was reluctant to buy due to concerns I've heard around achieving dark roasts, long roast time, and chaff collection. Not sure if my roaster is a newer batch or if I'm just lucky, but I haven't seen these problems for the most part and shouldn't have had any concerns at all.
This thing couldn't be easier to use - just put a few pieces in place and you're roasting 5 minutes after you open the box. Clean up is just as easy - simple dump of the chaff collector and quick blow out of loose chaff and you're doing your next batch - once you get a few days supply ready simply put the parts (not the main body, of course) in the dishwasher.
Achieving desired roast level has been a snap as well. I've done city, full city, and french roasts with no problems. Roast time varies based on the quantity of coffee you put in (there is a "normal" fill line, and a "dark roast" filll line), but with a full load I've been able to get a nice full city roast with a 26 setting (21 min's roasting plus 5 min cooling cycle), and a very dark, oily French roast in about the same amount of time with the roaster filled to the "dark roast" line. I've only used a couple of bean varieties, so I expect there will be some variation in these times - but achieving any roast level you want seems to be no problem. It's easy to add time on the fly if needed (up to 5 minutes), and you can instantly start the cooling cycle whenever you want - so as long as you have the original roast time setting in the right neighborhood the manual adjustments will take care of things. I set the timer to 30 for the first couple of roasts, and then used sight and sound to determine when to stop things - that process allowed me to zero in on the exact timer setting needed. Every roast done so far has been remarkably consistent - every bean is the same color and looks exactly like every other bean - this was a surprise as with the FR, all batches had some very light, and very dark beans mixed in any given roast.
I've seen where many people have problems hearing 1st and 2nd crack - this was my biggest concern. Learning on my FR, the cracks were the key to determining where the roast was at - so without them, how do I know what to do? Well, at least with my Z&D, hearing both cracks is not a problem. First crack is much quieter than with the FR, and I only hear a few dozen cracks over a couple minute period instead of the popcorn popping sound I get from the FR - but I've heard it easily with every roast thus far. Second crack sounds exactly like the FR and the cracks come fairly close together. With a full load, I typically get 1st crack in the 11-12 minute range, 2nd in the 19-20 minute range.
Chaff collection can be a problem depending on bean. Some varieties come out clean as a whistle - no chaff at all in the beans, while others do leave some stuff behind. Easy fix - due to the auger action the chaff is very fine (no large husks like those left in a FR roast) - so just dump the beans in a wire mesh colander, give it a shake or two, and no more chaff. I do recommend you have such a colander - you'll need it.
Probably the only negative I have with this thing is that the long roast time does seem to reduce the brightness in the cup - my experience is that you won't get the fruity/citrus/etc flavors that air roasting gives you. However, the cup has significantly more body. Since I much prefer a richer, deeper full bodied cup, this is actually a plus for me - but if you prefer lighter/brighter cups then you may have a problem. Take this with a grain of salt as the vast majority of my roasts have been a little on the dark side - if I spent some time playing with some lighter roasts, its quite possible that I could get more brightness - but you do need to be aware of this.
As for dealing with the company, you won't find anyone better to work with period. Even though I've not needed any true service, I've sent emails in with various questions and the folks at Z&D always respond immediately and go far and above simply giving a canned response. They have given suggestions, shared their personal experiences with the roaster, recommended beans that would fit with my taste preferences, and even dropped in a joke or two along the way. Absolutely best in class.
Although I'm glad I started with a FR to learn about the roast process, the cracks, etc, I wish I had gotten the Z&D months ago instead of waiting. Well built, high quality, great performance, outstanding customer service - just don't see how you could go wrong with this.