My rule of thumb is: If you torque it in your hands and it creaks, that says something about build quality.
I'll make my short list. Now, I don't have anything against these machines, but they were built cheaply to be affordable. So it's not like somebody didn't care about quality when they were designed.
DW-6000
Poly-800
TB-303
TR-707/727 or 505
First generation Electribes













