Buying a sewing machine
My concern for a home work use is to be carful. Industrial sewing machines tend to use industrial power, so ask if it will work with house hold power. Clutch driven machines are much simpler by design and tend to be cheaper to buy. Now if this machine has all the features needed for upholstery(single needle,walking foot) but has an industrial power motor(208/3phase)a single phase (120volt)clutch motor is not a very expensive purchase and converting the power switch has to be changed also(domestic light switch). A electronically controlled motor sewing machine more often has industrial power and it can be converted to a clutch drive motor but both type of machine conversions are at extra cost.
One more note, a sewing machine with electronic motors have more features than clutch driven machines(nice to have features,,needle positioner,back tack,etc)but if you install a clutch driven motor all features will be lost so get this machine cheap.
The faster the machine the better, the clutch speed is contoled by your foot pressure and with time you will want speed(just like cars).
Pfaff 1245 is hard machine to beat and a 1425 Pfaff is the Audi of walking foot needle feed machines.