FR8+ - 6 months or so. Great, simple, puched me along the learning curve. Too small for a serious coffee junkie, and my house has 2 of those.
iRoast - better part of a year, I guess? Excellent quality, easier to adjust profile than FR, and I could roast close to 1/2 pound at a shot. Sweet.
SC/CO (Yeah Dan, finally got it all put together) - past 6 months or so, after a serious shove by Mister M, who built me a metal SC drive shaft before I had a SC, or a CO. And you know if you have a drive shaft, you just GOTTA get the rest of the guts to use that sucker, no?. This is easily the champ overall. Great consistency, easy to adjust 'on the fly' and I've had luck with as much as a pound and a half at a time if you give it a nice warm-up period to start. Under $100 sourcing costs ($50 if you're real patient with eBay) , and 30 minutes to roast a week's worth of coffee. WooHoo!