I own a Cafe Roaster and was purchased through Monster Coffee. The roaster works great for my low volume I roast right now. I use some of monsters coffee blends for drip coffee and espressos. They just recently are now offering single origin green coffee as about half the cost so you can make your own signature blends. So far I have been very happy with the roaster if you are okay with roasting 3 to 4 lbs an hour - 1 lb roaster? I believe they run about $3,000.00. Here is they website they sell these roaster at if you want to inquire more? http://www.sonofresco.com/
I believe a drum roaster uses convectional heat and stirs the beans for an even roast by drum rotation. The beans heat slower so longer roasts are capable and the drum size is larger in comparison to a fluid bed (pop corn popper style forced hot air) roaster. I think the roasts you can get with a drum are toastier and perhaps sweeter given that it's easier to more fully caramelize a bean's sugar and take it past 1st crack without burning it.
A fluid bed, popcorn popper style roaster uses forced air to both roast and circulate the beans. They roast much faster and much more evenly since the forced air is constantly circulating all around the beans. However the increased degree of circulation and the smaller batch size of a fluid bed makes for a much faster roast. It's difficult to do a long roast with a fluid bed and the rest periods between 1st and 2nd crack end up being short, sometimes very short. Fluid bed roasts tend to be much brighter than drum roasts.
Fluid bed roaster like the Fresh Roast, i Roast, Zach & Dani's, popcorn poppers...are less expensive than drum roasters. They're also smaller and take up about the same space as a coffee maker.
So, I guess it depends on how much you want to roast at any one time, what kind of roast you prefer and how much you're willing to spend.
If you don't want to spend a lot of money there are other ways to roast beans besides a dedicated machine.
I like my airbed roaster...as it don't take up much room and so far not much maintenance and has been reliable for my low amount of roasting at the moment. Hoping that will change down the road then I will delve maybe into a drum roaster for 5 lb. roast quantities instead of my 1 lb. roasting as of now. I will still probably keep my 1 lb. roaster for sample testing/roasting.
For 1 lb. and under I think the fluid bed works great but if you need to roast more than 1 lb. at a time then are drum roasters better...that I am not sure about. I would love to hear an opinion or a link to a good site to read up on the differences and what makes one better over the other and why?