1 problem (another) is the uk ambient temp is quite allot 35+ to -5 . The Bullet is quite sensitive to varying ambent temps, so remember, you have to preheat for 20-30mins and then roast (12-15mins for 950g) Having an enclosed space makes the ambient reasonably manageable, as you can control the internal temp. Roasting consistantly outside (in the uk) would be very difficult. 1 more + though for the Bullet, for the hobbiest, roasting different beans is fun. For a commercial set up, you'll be roasting the same coffee again and again, which is not so fun and why having it automated like the bullet, makes it ok.