So much depends on set up. This is especially true when trying to relate to experience with GC's because there are so many out there and they have been tweaked and shimmed and lord knows what else, often by hacks that just funky up the performance and true character of the table.
This is especially true in pool halls where cost enters into it. When you are tightening the pockets on 30 tables it is way more cost effective to just shim the snot out of them than do it properly. Also, because GC's have been around so long the rails have been replaced over and over and again, usually by a hack since there are relatively few really good mechanics compared to the total population of guys that work on tables (especially the guys that work cheap).
Most people that have shot on a table that played funny don't really look closely at pocket angles, consistency of size from pocket to pocket, rail height etc. So they just assume that GC's aren't consistent. Well, they aren't after they've been hacked on umpteen times by various pseudo-professional mechanics.
I don't think Diamonds, at least the pro-cut Diamonds, get hacked on nearly as much because with the deep shelf you don't really want the pockets any tighter than the 4.5" that come from the factory. Plus there isn't this huge population of them that have filled pool halls for the last 50 years.
The deep shelves like on on the Diamonds are a matter of taste. Yes, that is one way to make a table play tougher but so is 3.5" pockets and I don't think anyone would say that is the way a table should be set up. It has pros and cons. I don't care to have a shot get spit out or hung up if it was struck accurately enough to go in the jaws. I have no problem with a shot hit along the rail requiring more accuracy than from the middle of the table but there has to be a happy medium. My experience with the pro cut Diamond was that it didn't seem to play unfair on those shots as opposed to say, an Olhausen, which is famous for rattlers. A well set up GC also requires more accuracy when playing along the rail, but a well struck shot can be hit at almost any speed and it will find gravity.
I've only had one real good session on a pro-cut Diamond, at the Tar Bar in Vegas this past May. I thought the table played real well and accepted shots much better than what I had expected from reading the threads on the matter here at AZB. This included shots down rail. I was very impressed with it and finally understood the buzz about them. I was playing very well that night though. :wink:
I've also heard the book on Diamonds is that they bank short. I can't speak to that but in any event I've also read around here that it is being addressed.
I own a GC4. My table was set-up with 4 1/4" pockets by Donny Wessel, so nuff said about that - it was constructed right and it plays right. I think Diamonds are an excellent table but I don't think they have anything over a properly set up GC.
Tell you what, you can pretty much get most any beat up GC out of a pool hall with buckets that has been pounded on by hacks for the last 30 years, take it home and have one of the elite mechanics around here set it up, and you will have yourself a world class pool table.
They are the two best tables - period. As some have said, there are some fairly subtle differences in the way they play, so any preference for one over the other is probably more a matter of taste than anything else. I prefer the way the Gold Crown plays, but that is just me. I can't argue with someone that prefers a Diamond either. That's just them. To each his own.
Just my point-oh-two.