Still looking for the perfect home roaster. Meanwhile, this is what I will use.
Positive Product Points
(1) Analog controls are simple and intuitive. (2) Components such as heater are readily available and you can install them yourself. (3) Not too noisy. (4) With care and practice you can get good roasts.
Negative Product Points
(1) Chaff collector is too hard to clean. Roasts are ruined if the chaff collector is not clean enough. (2) Cooldown is too slow. (3) Several components are prone to failure.
My comments about the chaff collector refer specifically to the original small one. I am probably going to upgrade to the larger one. "Cleaning" the small chaff collector refers to removing 10 screws and scraping or soaking off the material that sticks on the two screens. This has to be done every 10-20 roasts. Something that has to be done this often should not be a screwdriver job. If you do not do this, the machine has trouble reaching full temperature, and your roast quality will fall off unacceptably, especially for darker roasts.
The second problem is cooldown. The problem is not that cooldown takes too long overall, but that the beans will keep on roasting awhile after cooling starts. You can't just hit the stop button when your beans are cooked. You have to predict that your beans will be done in 60-90 seconds, and hit stop in advance, before they are done. This is especially hard with darker roasts where things can start moving very fast.
Third problem is that some components are prone to failure. In my case, the heating element failed after several years. There is someone who sells major components stateside, and I got a replacement part promptly. I had no problem dismantling the machine and installing the new part.
Results with this machine are not very repeatable. You can't just set a time and temperature, and go away and expect it to roast the same every time. It is too sensitive to the condition of the chaff screens, and is also sensitive to ambient temperature. Overall, good results require patience, practice, and alertness.
Despite those problems, the Gene is good relative to what is out there. I wish there was something better, but I haven't found it. I had thoughts about moving to a Hot Top because it handles the cool down issue better, but based on the reviews it seems to have its own problems and may not be enough better to justify the cost.
With the Gene, you just have to (1) at the end of your roast be in attendance and have had some practice; (2) keep the chaff collector clean; (3) expect to replace major parts every now and then.