Roasts home-size batches and gives you some control.
Surprisingly good smoke suppression.
Negative Product Points
Still best used in the garage.
Needs cleaning cycles.
Needs your full attention during roasts.
This is a slightly clunky machine and it takes some learning -- but given the technical problem of getting decent roasting at this price point and within consumer-product safety standards, I'm deeply impressed.
You select the amount of coffee you are putting in by pushing buttons for 1, 1/2, or 1/4 lbs., and the roaster sets maximum roasting times accordingly. This is designed to stop you burning your house down, a valid concern with any coffee roaster. The difference between a nice dark roast and a fire is maybe a minute, plus people are idiots. I've charred a couple batches myself through inattention.
If you want more roast options, you adjust the amounts. My standard batch is 10-12 oz on the one-pound setting, and I can get a very dark roast if that's what I want. Even if you don't want a dark roast, some green beans are very moist and need more time. But, especially if you're fibbing to the machine about how much coffee is in there, don't be wandering off during the roast. Put a comfortable chair by the roaster, bring a book, don't try to multi-task.
(If you read across the reviews you will see that quite a few of us have concluded that while you can roast a whole pound, you get the tastiest results and best control in the 8-12 oz range.)
I'm mainly roasting by ear. The window is nice, but it's hard to judge much by what you see there, and the smoke-suppression is good enough that smell won't guide you. But I have no problem hearing first and second crack. Because the transition from roasting to cooling does not cool the beans instantly, you may find 2nd crack continuing for 10-20 seconds after you hit cool.
Though I play with the profiles, I can't say I've found a good reason not to use P1.
When I started, I wanted to try as many different coffees as possible. But that wasn't good for learning how to roast, because there is so much variation between how different coffees behave in the roaster. I have learned best by buying four or more pounds of one kind of coffee and slowly working through it, roasting 10 oz, drinking it, roasting another 10 oz a little differently, drinking that... It takes me several roasts to figure out how to get what I want out of any one kind of coffee. Moreover, to be really geeky now, not every coffee does quite the standard sequence of a loud first crack, then silence, then a distinct second crack, and they don't all change color the same way, so you have to learn how to interpret each batch. I'm sure this is all obvious to experienced roasters, but it's part of the learning curve.
Very good. And Sweet Maria's rules for green coffee.
I recently did an overhaul, including belatedly cleaning the right-hand side of the roaster's inside (see picture in the Behmor material), which made a big difference. As far as I can work out, buildup of grime there makes the sensor on the other side of the wall give too-high readings resulting in less heat being applied to the roast. This can creep up on you. With the wall clean and shiny, roasts are snappier again and I can do more things.
Removing the cover on the outside of the machine, on the right is also a good idea, as indicated in the linked Behmor material. A *lot* of chaff had gotten in there.
Overall the machine is going strong, and I'm still doing a couple of 10 oz roasts more or less weekly. I have certainly done enough dark roasts to void the machine's warranty! I roast mainly on P4 now, as the profile giving me the most control. I also commonly do two roasts in a row, one caf and one decaf, despite instructions to give the Behmor a rest between roasts. Not that I want to encourage anyone to abuse the machine ... but it has stood up well to my abuse. I'm still a happy customer.