I don't have experience with it, per se. However, as a fan of both Cosmic Encounter and Dune, which is where the effect comes from, I can tell you a bit about it.
This is a fun, surprisingly powerful ability that makes for amazing games, cool plays and laughter. It also takes significant skill to use, as it's surprisingly easy to end up in the terrible "Look at your opponent's hand" scenario. However, it's also open-ended and can't be contained by any reasonable ruleset. There are an infinite number of ways to phrase the question in such a way that you can pretty much force the opponent to do what you want. For example, you can use conditionals like "If the answer to this question is no, will you..." to create some fairy ugly scenarios.
But look, you are playing casually and you can just agree not to use paradoxes, complex questions (as in, it's one question, not 4 nested ones) and other obvious bullshit. It's extremely unlikely you end up in a situation in which you "break the game" if you don't try very hard to abuse the mechanic. We have never had a problem playing with this effect in Cosmic and Dune, it just doesn't come up if you don't try to. Most bullshit isn't even good anyways, and you are better off asking the opponent if he'll play a certain card type. Wizards has also been smart enough to make it last only until the end of turn, which prevents 90% of the bullshit from happening. So great effect, fun mechanic, just be wary that it's intentionally open-ended in ways that can't be contained within a ruleset.
PD: Play Cosmic and Dune, they are amazing games.
