I have a Grizzly G0633 12" combination jointer/planer that started out with a 3-knife cutter head, but now has a spiral cutter head. The original cutter head failed after very little use (hobbyist woodworker). I originally thought it was bearings, but when I disassemled it, the bearings both still rotated, but the machined surface on the cutterhead was galled. To me it was clearly a manufacturing problem, but since it was a few months out of warranty, Grizzly charged me for a replacement. I was disappointed that they wouldn't go ahead and cover it, but it was out of the warranty period. Anyway, when the new cutterhead arrived, it was a spiral in a box marked with the part number of a 3-knife head - problem at the factory overseas. Then, they let me know that the head I needed was back-ordered and wouldn't be available for a few weeks. At this point I was pretty grouchy about the whole situation, but I finally got someone on the phone with the authority and willingness to do something reasonable to help me. Since I had already bought a cutter head, they just gave me the set of carbide cutters and screws to go with the spiral head, which I installed without problem in my machine. So, bottom line is that there were issues, but they came through to satisfy their customer. The machine now works great. My only complaint is the extruded aluminum fence, which isn't exactly true down its length. I coped with that by attaching a piece of plywood over it and shimming with aluminum foil tape to get it true. And the spiral head vs the 3-knife head? Pretty great. Would I buy another Grizzly machine? Yes.