I just purchased The Balls (the glorified ping pong balls training aid) and had my first long practice session with them. Here's my initial review. Out of the two balls, I found the light object ball to be significantly more useful than the light cue ball. Here's why:
The light cue ball -- In theory it seemed like this would allow a person to diagnose whether they are missing a straight shot due to accidental side as opposed to aiming wrong. However it's not that simple. I set up a few full table length straight shots with just the cue ball. I noticed some swerve on the initial shots (the light cue ball swerves A LOT when you put side on!), but after a few shots, I managed to start potting it consistently. I let a few of my friends try it and they all managed to pot it as well, most on the first try. We are not good players btw, and rarely find the center of the white on genuine straight shots. So why did we all do this easily? One difference is that when you just have a cue ball and no object ball, 100% of your focus is on the cue ball. This is different to a regular straight shot where you are flicking your eyes between the cue ball and object ball, and possibly micro-adjusting your line whilst trying to recenter on the white. Because of this it's significantly harder to find the center of the white on a real straight shot as opposed to simply hitting the cue ball towards the pocket. I found that most people, even if they are not that good at snooker, can find the center of the white under these artificial conditions quite well. So, I think it could be useful for people who genuinely cannot find the center, or very new players, or simply as a brief "tune-up" before moving onto the more beneficial exercises. It might also be useful for testing power shots, or the break in pool where a tiny amount of side is much more significant. It was also sometimes a little hard to tell if the cue ball was going off-line due to the initial deflection, or whether it was swerving back across its line, and therefore a little tricky to tell the difference between unintentional left and unintentional right.
The light object ball - Conversely I found using this ball with a regular heavy cue ball quite useful. It takes most of the unintentional side out of the equation. If you miss a shot using the light object ball and still follow the cue ball in, you can almost guarantee that you missed due to aim, not unintentional side. This is great for relieving the doubt and confusion over why you missed, and lets you really focus in on aim. For me personally, I found that potting the light object ball in this way is easier than a regular straight shot with 2 heavy balls. Even though the aiming tolerance is meant to be slightly harder, the elimination of side makes the pot easier. I think this is a great warm up exercise before doing regular straight shots. Where you really zero in on pure aiming, and don't worry about the cue ball deflection so much. Once your aim is tuned up and you're potting consistently. Then you switch to regular straight shots, and use exactly the same aiming process. If you start missing now, then it's quite likely that the culprit is unintentional side. So whilst you can't directly check for side this way, you can infer it by comparing between light object ball vs heavy object ball. Although it's still not always completely apparent which side you are accidently putting on, for example left side and missing due to deflection or right side and missing due to swerve and throw.
Both balls together - Personally I didn't find this exercise very beneficial for diagnostic purposes. All it really tells you is that you are either great at straight shots, or not so good. But with both balls together, you can no longer separate whether the miss was due to side or aiming. So it's fun as a challenge, but largely defeats the main purpose of this product for me.
Overall I'd say it's an interesting product. I like how you can somewhat isolate aiming from unintentional side, and really zero in on the aiming side. But I was a little disappointed that there was no way to directly isolate unintentional side in a realistic scenario involving a real straight shot with 2 balls. Due to this limitation, I feel it's not really for everyone. Some people will benefit from it more than others. But it's still interesting as a diagnostic tool.
Edit: Actually next time I go practice, I'm going to try something a bit different. Instead of just aiming the light cue ball at the pocket, I'm going to put an object ball in the jaws of the pocket and aim for that instead and try to see if it's hitting it roughly square on. I think this creates a more realistic cueing scenario. Hopefully that will make the light cue ball seem more relevant.
