I've used both. I started with a Whirly Pop and used it for about 1.5 years. It was OK. I definitely liked the beans, especially when compared to what is available locally for me. The smoke became an issue for my wife, but I liked it. The roast I sent to Tom was said to be good. When my plastic gears on the top of the popper degraded where I couldn't turn the beans adequately, ... I upgraded.
Now I've been using the Behmor for about 6 months and I love it. There is a convenience factor in terms of smoke suppression and largish batch size. But, for me, I like the roasts better out of the Behmor. They appear more even and more controlled. Of course, I have help with Ira's Behmor Thing program, which helps my simple mind tremendously. I like being able to change profiles and alter the roasting cycles with some degree, compared to the stove top.
I've considered the Hot Top for a future roaster, but I think I'll probably stick with Behmor due to its batch size, and relative simplicity. But of course, this is a way's off. ... oh, what's that honey, no, no, no, I'm not upgrading anymore, I'm perfectly content.
