Gee, a huge percentage of the folks in this forum are professional roasters. There are a few that use fluid-bed, which is kinda like using a popcorn popper.
Having said that, I can share what some of my customers have told me. There are some modifications that need to be made to the popcorn popper - I think it has to do with temperature control. Check around...there is probably some info on that.
One or two customers have found the older popcorn popper at garage sales and even eBay. It apparently has better temperature control than the new one.
You might also look at Zach & Dani's roaster...for the $150 it seems to be a well-liked roaster for my customers who roast at home.