I just did my 300th roast with the HotTop. It's a Monsooned Malabar that I took well into second crack. The HT is as close to perfect as a home roaster can get imo. I have the non-programmable model with digital display and I do all my roasts "by the seat of my pants." I started with 230g greens and have 198g roasted coffee. I got the greens from a fellow in Berlin for €6/kg.
Whether you save money by roasting will certainly depend upon how much you roast, where you get your greens, etc. It will also depend largely on luck, because if, like me, you roast about 69kg of green coffee without having to pay a penny for repairs you may well wind up saving money, but far more important, you will always be drinking fresh coffee roasted the way you like it.
There's just something that makes me itch about the thought of roasting to save money. Our passion here is a luxury, no question. I can think of many reasons to roast my own coffee, but saving money wouldn't be one of them.
Oh, and about the Behmor...read the complete review on Sweet Maria's before you even consider going any deeper into it.