When I was in the market for a cabinet saw 2 years ago, I was also deciding between the General 650 and the venerable PM66, leaning towards the 66 since most of my professional woodworking friends had them.
I ended up with the 650 for a number of reasons. I purchased it at a woodworking show which was really the only opportunity I had to check them both out side-by-side. I looked at the PM66 first and asked the PM rep a lot of questions and told him I was also looking at a General. Once he found out I was looking at a General, he basically proceeded to criticize everything about the General--except the saw itself or its features. He went on and on about how it's Canadian and how parts are hard to get and how they don't manufacture things as well as "we do in the States..." blah blah blah.
I went to the General booth and asked about the 650 and told the rep I was looking at the PM66. He said, "that's a great saw...here's where we've done things differently." He proceeded to go through features and focused on differences between the saws. I bought the General on the spot. So sales reps out there take note--there's a difference between knowing your competition and bashing your competition. The former informs your buyer; the latter makes you look like an idiot. The difference was worth a couple of grand that day.
I have other PM equipment--a jointer and a bandsaw--and I'm happy with those and with the customer service I've had on them. In the end it probably won't matter too much which saw you end up with. They're both great saws.