Your choice is between the two best tables. There are some differences in how they play, mainly related to the deeper shelf on the Diamond and how they bank. But the preference for one over the other is exactly that, a personal preference.
I own a GC4 and I personally prefer the way a GC plays, but that is just my personal choice. Having said that, I might recommend the Diamond in your situation but you should ask a couple more questions of the seller.
You should ask what version GC he is selling (GC1 - 5).This will give you an indication of it's age. With the Diamond ask if it has the pro cut pockets (4 1/2" corners). The problem with buying a used GC is that there are so many out there that have been in use for decades and have been hacked on by gosh knows who. Diamonds are usually newer and especially with the pro-cut models have probably been hacked on less. So you are more likely to get uniform pockets if they haven't been altered by anyone since they came out of the factory.
Don't know anything about your game or how serious a player you are, but a pro-cut Diamond will play tougher than most used Gold Crowns - the slate shelf is deeper into the pockets and most used GC's will generally have larger pockets than 4.5" and therefore play easier. If you and your friends are more casual players, then the GC may be the way to go.
My GC4 was in excellent condition but the pockets were too big. I had a qualified mechanic extend the sub-rails and bring the pockets down to 4.25", but this cost money.
Of course, if the table will be displayed in your home, then condition will play a part in your choice. Perhaps the seller can send you some detailed picks better showing the condition of the 2 tables.
Good luck, whichever you choose you will have a table you can enjoy for a long time. :grin-square:
Welcome to the forum!
