Gen 2 originally had a motor coupler (crucifix) that wasn’t drilled all the way through with a short motor coupling screw. This screw was prone to breaking off and the crucifix was known to strip out. They upgraded this and a new crucifix/screw/motor are available. There was also a free upgrade/fix sent out (if you called in with a problem) for the roll bunching up in the middle causing the unit to stall out out and you’d have to cut the fleece, empty the used side and reattach the fleece. It was just a hollow tube that you installed over one of the all thread screws holding the unit together. The motor on the g2 is also prone to dying at the 18-24 month mark and will need to be replaced ($80ish). The g3 unit is reportedly redesigned to have a different angle for the fleece to housing and a roller up top for less stress on the motor. It is also easier to change the fleece on. As for which one you should buy, it’s your money not mine. I’ve had a g2 for about 6 years. It’s great but has its downsides. The $80 motor every 18 months was an issue. You can get a $15 motor on Amazon if you can solder and drill the shaft. You can also print a motor housing for a higher torque motor.