I don't own a Diamond, but played extensively on pro-cut ProAm and own my own table. Here's my $0.02
Get the pro cut.
They aren't ridiculously tight. Someone said "fair" and I would agree. You can still slop a ball in catching the rail a bit.
"Tight" is 4-3/8" ...these play tough.
At first, pro cut Diamond seems very tight and tough compared to slop-buckets found in many pool rooms or consumer grade home tables. This can be a bit demoralizing at first, but that's only because your game has not been properly challenged. It doesn't take long to adjust. Fear not.
Facts, the pros play on 4.5" pockets. This is more and more becoming a standard as it is trickling down to more and more rooms. In the last 20 years or so, I've seen more rooms shimming down their pockets to match. More players are asking for them. New tables are being ordered with them.
The trend is toward smaller pockets, so as time goes on - you will be facing more and more pro-cut pockets. If you have a pro-cut table, you will feel right at home. You are future-proofing. If you go someplace and play on slop-buckets, you will shoot like a champion. Literally everything feels like it can go. You can cheat pockets. Confidence goes up and the stroke really starts flowing.
On the other hand, if you have looser pockets, and you play a league or a tournament on pro-cuts, you will always be making an adjustment every single time. You'll always have the same feeling weighing over you, in the back of your mind. Constantly sharking yourself.
By getting a pro-cut, you're taking charge of your game and playing on the best conditions.
And yes, it will make your game better as IF you want to pocket balls with the same ease - you will need to clean up your stroke and aim technique. That's a good thing.
Frustration is not a factor on pro-cut Diamonds. It is a real factor on smaller than 4.5 inch pocket tables for several reasons. One, the "smaller is better" has a limit. You cannot end up with pyramid table pockets. This changes the game. Being able to cheat a pocket, being able to shoot balls with high speed down the rail and other types of shots are an actual part of the game. Super small pockets begin to eliminate those aspects of the game that should be practiced. So taken to an extreme, there is a limit before it ceases being a familiar type of game.
The other factor is that the vast majority of pockets smaller than 4.5" do not have proper angular adjustments to stay reasonably playable. They often keep the same angle but just reduce the pocket. Worst is when 5" slop-bucket gold crowns are shimmed down to smaller than 4.5" it just becomes a garbage table.
RKC on this forum has talked about this quite a bit. When he reworks a table for 4.5" pockets, he does not shim them down by following the original angle. He changes the pocket angle...which requires decent woodworking skills. This is what makes it tight, but playable.
