Very interesting post here and also very accurate. I've owned a Diamond Pro-Am with one piece slate for six years now. Four years ago I had it converted from red label to blue label rails ($$$). It is imperative that I regularly check the tightness of the rails (bolts underneath) every month or so. They tend to come loose and the table develops roll offs. One other nagging problem that may be due to rail design is the difficulty in banking a ball that is on the side rail within an inch of the side pocket. Being a Bank Pool player this bothers me since there are certain shots that are unavailable on my table that I can shoot on a GC.
This brings up a larger issue that has only been briefly discussed on here so far. That is how different the Diamond plays from the GC. Very, very different is all I can say about that. It's a whole new learning curve to learn how to bank on a Diamond. Not only do the rails bank shorter, but there are shots that can be made on a Diamond that would be impossible on a GC. I was always pretty good about adapting to different table conditions but this one took me a long time to figure out (and I've never quite figured out the intricacies of holding balls on long rail banks and shooting three rails accurately). Let me just say that imo the GC banks correctly and the Diamond does not.
I agree with Bob Jewett about all the flaws in the design of the GC's, most of them having to do with the top and outside of the table and little to do with the construction and framework that holds everything up. I've owned many GC's in my poolrooms and in my home. The frames are built of robust and solid woods (no plywood here) and the slates are mostly the original Italian slate. GC's are robust and heavy tables, made to be durable under severe playing conditions (as in heavy usage every day). I've seen GC's that still are going strong after fifty years in the same poolroom.
Yes, I've busted my knuckles on them, torn my pants on the metal edges and had trouble shooting over the pockets and scoring wheels. But I got used to playing on them and what stands out for me was that when they were set up by a proper mechanic that would play good (and roll true!) for a very long time. In fact they wouldn't even need releveling until you were ready to change the cloth. A good, solid GC plays as good or better than any other table ever made imo.
Back to my Diamond. With the 4.25" corners this is one tough ass table to play on and is a very popular practice table for the pros who come through here. I like to say that if you can get in stroke on this table then you can play on any table.
I guess my dream table would be a GCV if I could find a good one. I love the look of that table. Maybe someone can tell me if they play as good as they look.
P.S. I had a Brunswick Sport King set up by Ernesto in my home many years ago (also 4.25" corners) and it played damn good!