For volume buy an Ambex, for the home by a FreshRoast.
Positive Product Points
Speed, ease of assembly/disassembly, few moving parts, quiet, reliability, easy to repeat roast results
Negative Product Points
No temp controls, no thermometer, lots of plastic
I got started in home roasting thanks to a Master roaster who is teaching me this art. He loaned me his FreshRoast to try out and I fell in love with it. I ordered my own from sweetmarias ($69 w/8 pack sampler) and have used it almost everyday since. It‘s easy to clean, quiet so I can hear the cracks of the beans, the glass chamber lets me watch the roast progress. The timer is a little off (I use a stopwatch too...makes life more repeatable). If you want more ability to repeat roasts add a thermometer, makes things more monitorable. Overall I‘m very excited with this machine.